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12.6. Date and Time Functions

This section describes the functions that can be used to manipulate temporal values. See Section 11.3, “Date and Time Types”, for a description of the range of values each date and time type has and the valid formats in which values may be specified.

Name Description
ADDDATE() Add dates
ADDTIME() Add time
CONVERT_TZ() Convert from one timezone to another
CURDATE() Return the current date
CURRENT_DATE(), CURRENT_DATE Synonyms for CURDATE()
CURRENT_TIME(), CURRENT_TIME Synonyms for CURTIME()
CURRENT_TIMESTAMP(), CURRENT_TIMESTAMP Synonyms for NOW()
CURTIME() Return the current time
DATE_ADD() Add two dates
DATE_FORMAT() Format date as specified
DATE_SUB() Subtract two dates
DATE() Extract the date part of a date or datetime expression
DATEDIFF() Subtract two dates
DAY() Synonym for DAYOFMONTH()
DAYNAME() Return the name of the weekday
DAYOFMONTH() Return the day of the month (1-31)
DAYOFWEEK() Return the weekday index of the argument
DAYOFYEAR() Return the day of the year (1-366)
EXTRACT Extract part of a date
FROM_DAYS() Convert a day number to a date
FROM_UNIXTIME() Format date as a UNIX timestamp
GET_FORMAT() Return a date format string
HOUR() Extract the hour
LAST_DAY Return the last day of the month for the argument
LOCALTIME(), LOCALTIME Synonym for NOW()
LOCALTIMESTAMP, LOCALTIMESTAMP() Synonym for NOW()
MAKEDATE() Create a date from the year and day of year
MAKETIME MAKETIME()
MICROSECOND() Return the microseconds from argument
MINUTE() Return the minute from the argument
MONTH() Return the month from the date passed
MONTHNAME() Return the name of the month
NOW() Return the current date and time
PERIOD_ADD() Add a period to a year-month
PERIOD_DIFF() Return the number of months between periods
QUARTER() Return the quarter from a date argument
SEC_TO_TIME() Converts seconds to 'HH:MM:SS' format
SECOND() Return the second (0-59)
STR_TO_DATE() Convert a string to a date
SUBDATE() When invoked with three arguments a synonym for DATE_SUB()
SUBTIME() Subtract times
SYSDATE() Return the time at which the function executes
TIME_FORMAT() Format as time
TIME_TO_SEC() Return the argument converted to seconds
TIME() Extract the time portion of the expression passed
TIMEDIFF() Subtract time
TIMESTAMP() With a single argument, this function returns the date or datetime expression. With two arguments, the sum of the arguments
TIMESTAMPADD() Add an interval to a datetime expression
TIMESTAMPDIFF() Subtract an interval from a datetime expression
TO_DAYS() Return the date argument converted to days
UNIX_TIMESTAMP() Return a UNIX timestamp
UTC_DATE() Return the current UTC date
UTC_TIME() Return the current UTC time
UTC_TIMESTAMP() Return the current UTC date and time
WEEK() Return the week number
WEEKDAY() Return the weekday index
WEEKOFYEAR() Return the calendar week of the date (1-53)
YEAR() Return the year
YEARWEEK() Return the year and week

Here is an example that uses date functions. The following query selects all rows with a date_col value from within the last 30 days: 

mysql> SELECT something FROM tbl_name
    -> WHERE DATE_SUB(CURDATE(),INTERVAL 30 DAY) <= date_col;

Note that the query also selects rows with dates that lie in the future.

Functions that expect date values usually accept datetime values and ignore the time part. Functions that expect time values usually accept datetime values and ignore the date part.

Functions that return the current date or time each are evaluated only once per query at the start of query execution. This means that multiple references to a function such as NOW() within a single query always produce the same result. This principle also applies to CURDATE(), CURTIME(), UTC_DATE(), UTC_TIME(), UTC_TIMESTAMP(), and to any of their synonyms.

Beginning with MySQL 4.1.3, the CURRENT_TIMESTAMP(), CURRENT_TIME(), CURRENT_DATE(), and FROM_UNIXTIME() functions return values in the connection's current time zone, which is available as the value of the time_zone system variable. In addition, UNIX_TIMESTAMP() assumes that its argument is a datetime value in the current time zone. See Section 5.10.8, “MySQL Server Time Zone Support”.

Some date functions can be used with “zero” dates or incomplete dates such as '2001-11-00', whereas others cannot. Functions that extract parts of dates typically work with incomplete dates. For example: 

mysql> SELECT DAYOFMONTH('2001-11-00'), MONTH('2005-00-00');
        -> 0, 0

Other functions expect complete dates and return NULL for incomplete dates. These include functions that perform date arithmetic or that map parts of dates to names. For example: 

mysql> SELECT DATE_ADD('2006-05-00',INTERVAL 1 DAY);
        -> NULL
mysql> SELECT DAYNAME('2006-05-00');
        -> NULL

  • ADDDATE(date,INTERVAL expr unit), ADDDATE(expr,days)

    When invoked with the INTERVAL form of the second argument, ADDDATE() is a synonym for DATE_ADD(). The related function SUBDATE() is a synonym for DATE_SUB(). For information on the INTERVAL unit argument, see the discussion for DATE_ADD(). 

    mysql> SELECT DATE_ADD('1998-01-02', INTERVAL 31 DAY);
        -> '1998-02-02'
mysql> SELECT ADDDATE('1998-01-02', INTERVAL 31 DAY);
        -> '1998-02-02'

    As of MySQL 4.1.1, the second syntax is allowed. When invoked with the days form of the second argument, MySQL treats it as an integer number of days to be added to expr. 

    mysql> SELECT ADDDATE('1998-01-02', 31);
        -> '1998-02-02'

  • ADDTIME(expr1,expr2)

    ADDTIME() adds expr2 to expr1 and returns the result. expr1 is a time or datetime expression, and expr2 is a time expression. 

    mysql> SELECT ADDTIME('1997-12-31 23:59:59.999999',
    ->                '1 1:1:1.000002');
        -> '1998-01-02 01:01:01.000001'
mysql> SELECT ADDTIME('01:00:00.999999', '02:00:00.999998');
        -> '03:00:01.999997'

    ADDTIME() was added in MySQL 4.1.1.

  • CONVERT_TZ(dt,from_tz,to_tz)

    CONVERT_TZ() converts a datetime value dt from the time zone given by from_tz to the time zone given by to_tz and returns the resulting value. Time zones are specified as described in Section 5.10.8, “MySQL Server Time Zone Support”. This function returns NULL if the arguments are invalid.

    If the value falls out of the supported range of the TIMESTAMP type when converted fom from_tz to UTC, no conversion occurs. The TIMESTAMP range is described in Section 11.1.2, “Overview of Date and Time Types”. 

    mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET');
        -> '2004-01-01 13:00:00'
mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','+00:00','+10:00');
        -> '2004-01-01 22:00:00'

    Note: To use named time zones such as 'MET' or 'Europe/Moscow', the time zone tables must be properly set up. See Section 5.10.8, “MySQL Server Time Zone Support”, for instructions.

    CONVERT_TZ() was added in MySQL 4.1.3.

    If you intend to use CONVERT_TZ() while other tables are locked with LOCK TABLES, you must also lock the mysql.time_zone_name table.

  • CURDATE()

    Returns the current date as a value in 'YYYY-MM-DD' or YYYYMMDD format, depending on whether the function is used in a string or numeric context. 

    mysql> SELECT CURDATE();
        -> '1997-12-15'
mysql> SELECT CURDATE() + 0;
        -> 19971215

  • CURRENT_DATE, CURRENT_DATE()

    CURRENT_DATE and CURRENT_DATE() are synonyms for CURDATE().

  • CURTIME()

    Returns the current time as a value in 'HH:MM:SS' or HHMMSS format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone. 

    mysql> SELECT CURTIME();
        -> '23:50:26'
mysql> SELECT CURTIME() + 0;
        -> 235026

  • CURRENT_TIME, CURRENT_TIME()

    CURRENT_TIME and CURRENT_TIME() are synonyms for CURTIME().

  • CURRENT_TIMESTAMP, CURRENT_TIMESTAMP()

    CURRENT_TIMESTAMP and CURRENT_TIMESTAMP() are synonyms for NOW().

  • DATE(expr)

    Extracts the date part of the date or datetime expression expr. 

    mysql> SELECT DATE('2003-12-31 01:02:03');
        -> '2003-12-31'

    DATE() is available as of MySQL 4.1.1.

  • DATEDIFF(expr1,expr2)

    DATEDIFF() returns expr1 – expr2 expressed as a value in days from one date to the other. expr1 and expr2 are date or date-and-time expressions. Only the date parts of the values are used in the calculation. 

    mysql> SELECT DATEDIFF('1997-12-31 23:59:59','1997-12-30');
        -> 1
mysql> SELECT DATEDIFF('1997-11-30 23:59:59','1997-12-31');
        -> -31

    DATEDIFF() was added in MySQL 4.1.1.

  • DATE_ADD(date,INTERVAL expr unit), DATE_SUB(date,INTERVAL expr unit)

    These functions perform date arithmetic. date is a DATETIME or DATE value specifying the starting date. expr is an expression specifying the interval value to be added or subtracted from the starting date. expr is a string; it may start with a ‘-’ for negative intervals. unit is a keyword indicating the units in which the expression should be interpreted.

    The INTERVAL keyword and the unit specifier are not case sensitive.

    The following table shows the expected form of the expr argument for each unit value.

    unit Value Expected expr Format Version
    MICROSECOND MICROSECONDS 4.1.1
    SECOND SECONDS Pre-4.1
    MINUTE MINUTES Pre-4.1
    HOUR HOURS Pre-4.1
    DAY DAYS Pre-4.1
    WEEK WEEKS 5.0.0
    MONTH MONTHS Pre-4.1
    QUARTER QUARTERS 5.0.0
    YEAR YEARS Pre-4.1
    SECOND_MICROSECOND 'SECONDS.MICROSECONDS' 4.1.1
    MINUTE_MICROSECOND 'MINUTES.MICROSECONDS' 4.1.1
    MINUTE_SECOND 'MINUTES:SECONDS' 4.1.1
    HOUR_MICROSECOND 'HOURS.MICROSECONDS' 4.1.1
    HOUR_SECOND 'HOURS:MINUTES:SECONDS' 4.1.1
    HOUR_MINUTE 'HOURS:MINUTES' Pre-4.1
    DAY_MICROSECOND 'DAYS.MICROSECONDS' 4.1.1
    DAY_SECOND 'DAYS HOURS:MINUTES:SECONDS' Pre-4.1
    DAY_MINUTE 'DAYS HOURS:MINUTES' Pre-4.1
    DAY_HOUR 'DAYS HOURS' Pre-4.1
    YEAR_MONTH 'YEARS-MONTHS' Pre-4.1

    The type values DAY_MICROSECOND, HOUR_MICROSECOND, MINUTE_MICROSECOND, SECOND_MICROSECOND, and MICROSECOND are allowed as of MySQL 4.1.1.

    MySQL allows any punctuation delimiter in the expr format. Those shown in the table are the suggested delimiters. If the date argument is a DATE value and your calculations involve only YEAR, MONTH, and DAY parts (that is, no time parts), the result is a DATE value. Otherwise, the result is a DATETIME value.

    As of MySQL 3.23, date arithmetic also can be performed using INTERVAL together with the + or - operator: 

    date + INTERVAL expr unit
date - INTERVAL expr unit

    INTERVAL expr unit is allowed on either side of the + operator if the expression on the other side is a date or datetime value. For the - operator, INTERVAL expr unit is allowed only on the right side, because it makes no sense to subtract a date or datetime value from an interval. 

    mysql> SELECT '1997-12-31 23:59:59' + INTERVAL 1 SECOND;
        -> '1998-01-01 00:00:00'
mysql> SELECT INTERVAL 1 DAY + '1997-12-31';
        -> '1998-01-01'
mysql> SELECT '1998-01-01' - INTERVAL 1 SECOND;
        -> '1997-12-31 23:59:59'
mysql> SELECT DATE_ADD('1997-12-31 23:59:59',
    ->                 INTERVAL 1 SECOND);
        -> '1998-01-01 00:00:00'
mysql> SELECT DATE_ADD('1997-12-31 23:59:59',
    ->                 INTERVAL 1 DAY);
        -> '1998-01-01 23:59:59'
mysql> SELECT DATE_ADD('1997-12-31 23:59:59',
    ->                 INTERVAL '1:1' MINUTE_SECOND);
        -> '1998-01-01 00:01:00'
mysql> SELECT DATE_SUB('1998-01-01 00:00:00',
    ->                 INTERVAL '1 1:1:1' DAY_SECOND);
        -> '1997-12-30 22:58:59'
mysql> SELECT DATE_ADD('1998-01-01 00:00:00',
    ->                 INTERVAL '-1 10' DAY_HOUR);
        -> '1997-12-30 14:00:00'
mysql> SELECT DATE_SUB('1998-01-02', INTERVAL 31 DAY);
        -> '1997-12-02'
mysql> SELECT DATE_ADD('1992-12-31 23:59:59.000002',
    ->            INTERVAL '1.999999' SECOND_MICROSECOND);
        -> '1993-01-01 00:00:01.000001'

    If you specify an interval value that is too short (does not include all the interval parts that would be expected from the unit keyword), MySQL assumes that you have left out the leftmost parts of the interval value. For example, if you specify a unit of DAY_SECOND, the value of expr is expected to have days, hours, minutes, and seconds parts. If you specify a value like '1:10', MySQL assumes that the days and hours parts are missing and the value represents minutes and seconds. In other words, '1:10' DAY_SECOND is interpreted in such a way that it is equivalent to '1:10' MINUTE_SECOND. This is analogous to the way that MySQL interprets TIME values as representing elapsed time rather than as a time of day.

    If you add to or subtract from a date value something that contains a time part, the result is automatically converted to a datetime value: 

    mysql> SELECT DATE_ADD('1999-01-01', INTERVAL 1 DAY);
        -> '1999-01-02'
mysql> SELECT DATE_ADD('1999-01-01', INTERVAL 1 HOUR);
        -> '1999-01-01 01:00:00'

    If you add MONTH, YEAR_MONTH, or YEAR and the resulting date has a day that is larger than the maximum day for the new month, the day is adjusted to the maximum days in the new month: 

    mysql> SELECT DATE_ADD('1998-01-30', INTERVAL 1 MONTH);
        -> '1998-02-28'

    Date arithmetic operations require complete dates and do not work with incomplete dates such as '2006-07-00' or badly malformed dates: 

    mysql> SELECT DATE_ADD('2006-07-00', INTERVAL 1 DAY);
        -> NULL
mysql> SELECT '2005-03-32' + INTERVAL 1 MONTH;
        -> NULL

  • DATE_FORMAT(date,format)

    Formats the date value according to the format string.

    The following specifiers may be used in the format string. As of MySQL 3.23, the ‘%’ character is required before format specifier characters. In earlier versions of MySQL, ‘%’ was optional.

    Specifier Description
    %a Abbreviated weekday name (Sun..Sat)
    %b Abbreviated month name (Jan..Dec)
    %c Month, numeric (0..12)
    %D Day of the month with English suffix (0th, 1st, 2nd, 3rd, …)
    %d Day of the month, numeric (00..31)
    %e Day of the month, numeric (0..31)
    %f Microseconds (000000..999999)
    %H Hour (00..23)
    %h Hour (01..12)
    %I Hour (01..12)
    %i Minutes, numeric (00..59)
    %j Day of year (001..366)
    %k Hour (0..23)
    %l Hour (1..12)
    %M Month name (January..December)
    %m Month, numeric (00..12)
    %p AM or PM
    %r Time, 12-hour (hh:mm:ss followed by AM or PM)
    %S Seconds (00..59)
    %s Seconds (00..59)
    %T Time, 24-hour (hh:mm:ss)
    %U Week (00..53), where Sunday is the first day of the week
    %u Week (00..53), where Monday is the first day of the week
    %V Week (01..53), where Sunday is the first day of the week; used with %X
    %v Week (01..53), where Monday is the first day of the week; used with %x
    %W Weekday name (Sunday..Saturday)
    %w Day of the week (0=Sunday..6=Saturday)
    %X Year for the week where Sunday is the first day of the week, numeric, four digits; used with %V
    %x Year for the week, where Monday is the first day of the week, numeric, four digits; used with %v
    %Y Year, numeric, four digits
    %y Year, numeric (two digits)
    %% A literal ‘%’ character
    %x x, for any ‘x’ not listed above

    The %v, %V, %x, and %X format specifiers are available as of MySQL 3.23.8. %f is available as of MySQL 4.1.1.

    Ranges for the month and day specifiers begin with zero due to the fact that MySQL allows the storing of incomplete dates such as '2004-00-00' (as of MySQL 3.23).

    As of MySQL 4.1.21, the language used for day and month names and abbreviations is controlled by the value of the lc_time_names system variable (Section 5.10.9, “MySQL Server Locale Support”).

    As of MySQL 4.1.23, DATE_FORMAT() returns a string with a character set and collation given by character_set_connection and collation_connection so that it can return month and weekday names containing non-ASCII characters. Before 4.1.23, the return value is a binary string. 

    mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00', '%W %M %Y');
        -> 'Saturday October 1997'
mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00', '%H:%i:%s');
        -> '22:23:00'
mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00',
                          '%D %y %a %d %m %b %j');
        -> '4th 97 Sat 04 10 Oct 277'
mysql> SELECT DATE_FORMAT('1997-10-04 22:23:00',
                          '%H %k %I %r %T %S %w');
        -> '22 22 10 10:23:00 PM 22:23:00 00 6'
mysql> SELECT DATE_FORMAT('1999-01-01', '%X %V');
        -> '1998 52'
mysql> SELECT DATE_FORMAT('2006-06-00', '%d');
        -> '00'

  • DATE_SUB(date,INTERVAL expr unit)

    See DATE_ADD().

  • DAY(date)

    DAY() is a synonym for DAYOFMONTH(). It is available as of MySQL 4.1.1.

  • DAYNAME(date)

    Returns the name of the weekday for date. As of MySQL 4.1.21, the language used for the name is controlled by the value of the lc_time_names system variable (Section 5.10.9, “MySQL Server Locale Support”). 

    mysql> SELECT DAYNAME('1998-02-05');
        -> 'Thursday'

  • DAYOFMONTH(date)

    Returns the day of the month for date, in the range 0 to 31. 

    mysql> SELECT DAYOFMONTH('1998-02-03');
        -> 3

  • DAYOFWEEK(date)

    Returns the weekday index for date (1 = Sunday, 2 = Monday, …, 7 = Saturday). These index values correspond to the ODBC standard. 

    mysql> SELECT DAYOFWEEK('1998-02-03');
        -> 3

  • DAYOFYEAR(date)

    Returns the day of the year for date, in the range 1 to 366. 

    mysql> SELECT DAYOFYEAR('1998-02-03');
        -> 34

  • EXTRACT(unit FROM date)

    The EXTRACT() function uses the same kinds of unit specifiers as DATE_ADD() or DATE_SUB(), but extracts parts from the date rather than performing date arithmetic. 

    mysql> SELECT EXTRACT(YEAR FROM '1999-07-02');
       -> 1999
mysql> SELECT EXTRACT(YEAR_MONTH FROM '1999-07-02 01:02:03');
       -> 199907
mysql> SELECT EXTRACT(DAY_MINUTE FROM '1999-07-02 01:02:03');
       -> 20102
mysql> SELECT EXTRACT(MICROSECOND
    ->                FROM '2003-01-02 10:30:00.000123');
        -> 123

    EXTRACT() was added in MySQL 3.23.0.

  • FROM_DAYS(N)

    Given a day number N, returns a DATE value. 

    mysql> SELECT FROM_DAYS(729669);
        -> '1997-10-07'

    Use FROM_DAYS() with caution on old dates. It is not intended for use with values that precede the advent of the Gregorian calendar (1582). See Section 12.7, “What Calendar Is Used By MySQL?”.

  • FROM_UNIXTIME(unix_timestamp), FROM_UNIXTIME(unix_timestamp,format)

    Returns a representation of the unix_timestamp argument as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone. unix_timestamp is an internal timestamp value such as is produced by the UNIX_TIMESTAMP() function.

    If format is given, the result is formatted according to the format string, which is used the same way as listed in the entry for the DATE_FORMAT() function. 

    mysql> SELECT FROM_UNIXTIME(875996580);
        -> '1997-10-04 22:23:00'
mysql> SELECT FROM_UNIXTIME(875996580) + 0;
        -> 19971004222300
mysql> SELECT FROM_UNIXTIME(UNIX_TIMESTAMP(),
    ->                      '%Y %D %M %h:%i:%s %x');
        -> '2003 6th August 06:22:58 2003'

    Note: If you use UNIX_TIMESTAMP() and FROM_UNIXTIME() to convert between TIMESTAMP values and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For details, see the description of the UNIX_TIMESTAMP() function.

  • GET_FORMAT(DATE|TIME|DATETIME, 'EUR'|'USA'|'JIS'|'ISO'|'INTERNAL')

    Returns a format string. This function is useful in combination with the DATE_FORMAT() and the STR_TO_DATE() functions.

    The possible values for the first and second arguments result in several possible format strings (for the specifiers used, see the table in the DATE_FORMAT() function description). ISO format refers to ISO 9075, not ISO 8601.

    Function Call Result
    GET_FORMAT(DATE,'USA') '%m.%d.%Y'
    GET_FORMAT(DATE,'JIS') '%Y-%m-%d'
    GET_FORMAT(DATE,'ISO') '%Y-%m-%d'
    GET_FORMAT(DATE,'EUR') '%d.%m.%Y'
    GET_FORMAT(DATE,'INTERNAL') '%Y%m%d'
    GET_FORMAT(DATETIME,'USA') '%Y-%m-%d %H.%i.%s'
    GET_FORMAT(DATETIME,'JIS') '%Y-%m-%d %H:%i:%s'
    GET_FORMAT(DATETIME,'ISO') '%Y-%m-%d %H:%i:%s'
    GET_FORMAT(DATETIME,'EUR') '%Y-%m-%d %H.%i.%s'
    GET_FORMAT(DATETIME,'INTERNAL') '%Y%m%d%H%i%s'
    GET_FORMAT(TIME,'USA') '%h:%i:%s %p'
    GET_FORMAT(TIME,'JIS') '%H:%i:%s'
    GET_FORMAT(TIME,'ISO') '%H:%i:%s'
    GET_FORMAT(TIME,'EUR') '%H.%i.%s'
    GET_FORMAT(TIME,'INTERNAL') '%H%i%s'

    As of MySQL 4.1.4, TIMESTAMP can also be used as the first argument to GET_FORMAT(), in which case the function returns the same values as for DATETIME. 

    mysql> SELECT DATE_FORMAT('2003-10-03',GET_FORMAT(DATE,'EUR'));
        -> '03.10.2003'
mysql> SELECT STR_TO_DATE('10.31.2003',GET_FORMAT(DATE,'USA'));
        -> '2003-10-31'

    GET_FORMAT() is available as of MySQL 4.1.1.

  • HOUR(time)

    Returns the hour for time. The range of the return value is 0 to 23 for time-of-day values. However, the range of TIME values actually is much larger, so HOUR can return values greater than 23. 

    mysql> SELECT HOUR('10:05:03');
        -> 10
mysql> SELECT HOUR('272:59:59');
        -> 272

  • LAST_DAY(date)

    Takes a date or datetime value and returns the corresponding value for the last day of the month. Returns NULL if the argument is invalid. 

    mysql> SELECT LAST_DAY('2003-02-05');
        -> '2003-02-28'
mysql> SELECT LAST_DAY('2004-02-05');
        -> '2004-02-29'
mysql> SELECT LAST_DAY('2004-01-01 01:01:01');
        -> '2004-01-31'
mysql> SELECT LAST_DAY('2003-03-32');
        -> NULL

    LAST_DAY() is available as of MySQL 4.1.1.

  • LOCALTIME, LOCALTIME()

    LOCALTIME and LOCALTIME() are synonyms for NOW().

  • LOCALTIMESTAMP, LOCALTIMESTAMP()

    LOCALTIMESTAMP and LOCALTIMESTAMP() are synonyms for NOW().

    They were added in MySQL 4.0.6.

  • MAKEDATE(year,dayofyear)

    Returns a date, given year and day-of-year values. dayofyear must be greater than 0 or the result is NULL. 

    mysql> SELECT MAKEDATE(2001,31), MAKEDATE(2001,32);
        -> '2001-01-31', '2001-02-01'
mysql> SELECT MAKEDATE(2001,365), MAKEDATE(2004,365);
        -> '2001-12-31', '2004-12-30'
mysql> SELECT MAKEDATE(2001,0);
        -> NULL

    MAKEDATE() is available as of MySQL 4.1.1.

  • MAKETIME(hour,minute,second)

    Returns a time value calculated from the hour, minute, and second arguments. 

    mysql> SELECT MAKETIME(12,15,30);
        -> '12:15:30'

    MAKETIME() is available as of MySQL 4.1.1.

  • MICROSECOND(expr)

    Returns the microseconds from the time or datetime expression expr as a number in the range from 0 to 999999. 

    mysql> SELECT MICROSECOND('12:00:00.123456');
        -> 123456
mysql> SELECT MICROSECOND('1997-12-31 23:59:59.000010');
        -> 10

    MICROSECOND() is available as of MySQL 4.1.1.

  • MINUTE(time)

    Returns the minute for time, in the range 0 to 59. 

    mysql> SELECT MINUTE('98-02-03 10:05:03');
        -> 5

  • MONTH(date)

    Returns the month for date, in the range 0 to 12. 

    mysql> SELECT MONTH('1998-02-03');
        -> 2

  • MONTHNAME(date)

    Returns the full name of the month for date. As of MySQL 4.1.21, the language used for the name is controlled by the value of the lc_time_names system variable (Section 5.10.9, “MySQL Server Locale Support”). 

    mysql> SELECT MONTHNAME('1998-02-05');
        -> 'February'

  • NOW()

    Returns the current date and time as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone. 

    mysql> SELECT NOW();
        -> '1997-12-15 23:50:26'
mysql> SELECT NOW() + 0;
        -> 19971215235026

  • PERIOD_ADD(P,N)

    Adds N months to period P (in the format YYMM or YYYYMM). Returns a value in the format YYYYMM. Note that the period argument P is not a date value. 

    mysql> SELECT PERIOD_ADD(9801,2);
        -> 199803

  • PERIOD_DIFF(P1,P2)

    Returns the number of months between periods P1 and P2. P1 and P2 should be in the format YYMM or YYYYMM. Note that the period arguments P1 and P2 are not date values. 

    mysql> SELECT PERIOD_DIFF(9802,199703);
        -> 11

  • QUARTER(date)

    Returns the quarter of the year for date, in the range 1 to 4. 

    mysql> SELECT QUARTER('98-04-01');
        -> 2

  • SECOND(time)

    Returns the second for time, in the range 0 to 59. 

    mysql> SELECT SECOND('10:05:03');
        -> 3

  • SEC_TO_TIME(seconds)

    Returns the seconds argument, converted to hours, minutes, and seconds, as a value in 'HH:MM:SS' or HHMMSS format, depending on whether the function is used in a string or numeric context. 

    mysql> SELECT SEC_TO_TIME(2378);
        -> '00:39:38'
mysql> SELECT SEC_TO_TIME(2378) + 0;
        -> 3938

    Note: You cannot use format "%X%V" to convert a year-week string to a date because the combination of a year and week does not uniquely identify a year and month if the week crosses a month boundary. To convert a year-week to a date, then you should also specify the weekday: 

    mysql> SELECT STR_TO_DATE('200442 Monday', '%X%V %W');
        -> '2004-10-18'

  • STR_TO_DATE(str,format)

    This is the inverse of the DATE_FORMAT() function. It takes a string str and a format string format. STR_TO_DATE() returns a DATETIME value if the format string contains both date and time parts, or a DATE or TIME value if the string contains only date or time parts.

    The date, time, or datetime values contained in str should be given in the format indicated by format. For the specifiers that can be used in format, see the DATE_FORMAT() function description. If str contains an illegal date, time, or datetime value, STR_TO_DATE() returns NULL.

    Range checking on the parts of date values is as described in Section 11.3.1, “The DATETIME, DATE, and TIMESTAMP Types”. This means, for example, that a date with a day part larger than the number of days in a month is allowable as long as the day part is in the range from 1 to 31. Also, “zero” dates or dates with part values of 0 are allowed. 

    mysql> SELECT STR_TO_DATE('00/00/0000', '%m/%d/%Y');
        -> '0000-00-00'
mysql> SELECT STR_TO_DATE('04/31/2004', '%m/%d/%Y');
        -> '2004-04-31'

    STR_TO_DATE() is available as of MySQL 4.1.1.

  • SUBDATE(date,INTERVAL expr unit), SUBDATE(expr,days)

    When invoked with the INTERVAL form of the second argument, SUBDATE() is a synonym for DATE_SUB(). For information on the INTERVAL unit argument, see the discussion for DATE_ADD(). 

    mysql> SELECT DATE_SUB('1998-01-02', INTERVAL 31 DAY);
        -> '1997-12-02'
mysql> SELECT SUBDATE('1998-01-02', INTERVAL 31 DAY);
        -> '1997-12-02'

    As of MySQL 4.1.1, the second syntax is allowed, where expr is a date or datetime expression and days is the number of days to be subtracted from expr. 

    mysql> SELECT SUBDATE('1998-01-02 12:00:00', 31);
        -> '1997-12-02 12:00:00'

  • SUBTIME(expr1,expr2)

    SUBTIME() returns expr1 – expr2 expressed as a value in the same format as expr1. expr1 is a time or datetime expression, and expr2 is a time expression. 

    mysql> SELECT SUBTIME('1997-12-31 23:59:59.999999','1 1:1:1.000002');
        -> '1997-12-30 22:58:58.999997'
mysql> SELECT SUBTIME('01:00:00.999999', '02:00:00.999998');
        -> '-00:59:59.999999'

    SUBTIME() was added in MySQL 4.1.1.

  • SYSDATE()

    Returns the current date and time as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS format, depending on whether the function is used in a string or numeric context.

  • TIME(expr)

    Extracts the time part of the time or datetime expression expr and returns it as a string. 

    mysql> SELECT TIME('2003-12-31 01:02:03');
        -> '01:02:03'
mysql> SELECT TIME('2003-12-31 01:02:03.000123');
        -> '01:02:03.000123'

    TIME() is available as of MySQL 4.1.1.

  • TIMEDIFF(expr1,expr2)

    TIMEDIFF() returns expr1 – expr2 expressed as a time value. expr1 and expr2 are time or date-and-time expressions, but both must be of the same type. 

    mysql> SELECT TIMEDIFF('2000:01:01 00:00:00',
    ->                 '2000:01:01 00:00:00.000001');
        -> '-00:00:00.000001'
mysql> SELECT TIMEDIFF('1997-12-31 23:59:59.000001',
    ->                 '1997-12-30 01:01:01.000002');
        -> '46:58:57.999999'

    TIMEDIFF() was added in MySQL 4.1.1.

  • TIMESTAMP(expr), TIMESTAMP(expr1,expr2)

    With a single argument, this function returns the date or datetime expression expr as a datetime value. With two arguments, it adds the time expression expr2 to the date or datetime expression expr1 and returns the result as a datetime value. 

    mysql> SELECT TIMESTAMP('2003-12-31');
        -> '2003-12-31 00:00:00'
mysql> SELECT TIMESTAMP('2003-12-31 12:00:00','12:00:00');
        -> '2004-01-01 00:00:00'

    TIMESTAMP() is available as of MySQL 4.1.1.

  • TIME_FORMAT(time,format)

    This is used like the DATE_FORMAT() function, but the format string may contain format specifiers only for hours, minutes, and seconds. Other specifiers produce a NULL value or 0.

    If the time value contains an hour part that is greater than 23, the %H and %k hour format specifiers produce a value larger than the usual range of 0..23. The other hour format specifiers produce the hour value modulo 12. 

    mysql> SELECT TIME_FORMAT('100:00:00', '%H %k %h %I %l');
        -> '100 100 04 04 4'

  • TIME_TO_SEC(time)

    Returns the time argument, converted to seconds. 

    mysql> SELECT TIME_TO_SEC('22:23:00');
        -> 80580
mysql> SELECT TIME_TO_SEC('00:39:38');
        -> 2378

  • TO_DAYS(date)

    Given a date date, returns a day number (the number of days since year 0). 

    mysql> SELECT TO_DAYS(950501);
        -> 728779
mysql> SELECT TO_DAYS('1997-10-07');
        -> 729669

    TO_DAYS() is not intended for use with values that precede the advent of the Gregorian calendar (1582), because it does not take into account the days that were lost when the calendar was changed. For dates before 1582 (and possibly a later year in other locales), results from this function are not reliable. See Section 12.7, “What Calendar Is Used By MySQL?”, for details.

    Remember that MySQL converts two-digit year values in dates to four-digit form using the rules in Section 11.3, “Date and Time Types”. For example, '1997-10-07' and '97-10-07' are seen as identical dates: 

    mysql> SELECT TO_DAYS('1997-10-07'), TO_DAYS('97-10-07');
        -> 729669, 729669

  • UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date)

    If called with no argument, returns a Unix timestamp (seconds since '1970-01-01 00:00:00' UTC) as an unsigned integer. If UNIX_TIMESTAMP() is called with a date argument, it returns the value of the argument as seconds since '1970-01-01 00:00:00' UTC. date may be a DATE string, a DATETIME string, a TIMESTAMP, or a number in the format YYMMDD or YYYYMMDD. The server interprets date as a value in the current time zone and converts it to an internal value in UTC. Clients can set their time zone as described in Section 5.10.8, “MySQL Server Time Zone Support”. 

    mysql> SELECT UNIX_TIMESTAMP();
        -> 882226357
mysql> SELECT UNIX_TIMESTAMP('1997-10-04 22:23:00');
        -> 875996580

    When UNIX_TIMESTAMP is used on a TIMESTAMP column, the function returns the internal timestamp value directly, with no implicit “string-to-Unix-timestamp” conversion. If you pass an out-of-range date to UNIX_TIMESTAMP(), it returns 0, but please note that only basic range checking is performed (year from 1970 to 2038, month from 01 to 12, day from 01 from 31).

    Note: If you use UNIX_TIMESTAMP() and FROM_UNIXTIME() to convert between TIMESTAMP values and Unix timestamp values, the conversion is lossy because the mapping is not one-to-one in both directions. For example, due to conventions for local time zone changes, it is possible for two UNIX_TIMESTAMP() to map two TIMESTAMP values to the same Unix timestamp value. FROM_UNIXTIME() will map that value back to only one of the original TIMESTAMP values. Here is an example, using TIMESTAMP values in the CET time zone: 

    mysql> SELECT UNIX_TIMESTAMP('2005-03-27 03:00:00');
+---------------------------------------+
| UNIX_TIMESTAMP('2005-03-27 03:00:00') |
+---------------------------------------+
|                            1111885200 |
+---------------------------------------+
mysql> SELECT UNIX_TIMESTAMP('2005-03-27 02:00:00');
+---------------------------------------+
| UNIX_TIMESTAMP('2005-03-27 02:00:00') |
+---------------------------------------+
|                            1111885200 |
+---------------------------------------+
mysql> SELECT FROM_UNIXTIME(1111885200);
+---------------------------+
| FROM_UNIXTIME(1111885200) |
+---------------------------+
| 2005-03-27 03:00:00       |
+---------------------------+

    If you want to subtract UNIX_TIMESTAMP() columns, you might want to cast the result to signed integers. See Section 12.9, “Cast Functions and Operators”.

  • UTC_DATE, UTC_DATE()

    Returns the current UTC date as a value in 'YYYY-MM-DD' or YYYYMMDD format, depending on whether the function is used in a string or numeric context. 

    mysql> SELECT UTC_DATE(), UTC_DATE() + 0;
        -> '2003-08-14', 20030814

    UTC_DATE() is available as of MySQL 4.1.1.

  • UTC_TIME, UTC_TIME()

    Returns the current UTC time as a value in 'HH:MM:SS' or HHMMSS format, depending on whether the function is used in a string or numeric context. 

    mysql> SELECT UTC_TIME(), UTC_TIME() + 0;
        -> '18:07:53', 180753

    UTC_TIME() is available as of MySQL 4.1.1.

  • UTC_TIMESTAMP, UTC_TIMESTAMP()

    Returns the current UTC date and time as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS format, depending on whether the function is used in a string or numeric context. 

    mysql> SELECT UTC_TIMESTAMP(), UTC_TIMESTAMP() + 0;
        -> '2003-08-14 18:08:04', 20030814180804

    UTC_TIMESTAMP() is available as of MySQL 4.1.1.

  • WEEK(date[,mode])

    This function returns the week number for date. The two-argument form of WEEK() allows you to specify whether the week starts on Sunday or Monday and whether the return value should be in the range from 0 to 53 or from 1 to 53. If the mode argument is omitted, the value of the default_week_format system variable is used (or 0 before MySQL 4.0.14). See Section 5.2.3, “System Variables”.

    The following table describes how the mode argument works.

      First day    
    Mode of week Range Week 1 is the first week …
    0 Sunday 0-53 with a Sunday in this year
    1 Monday 0-53 with more than 3 days this year
    2 Sunday 1-53 with a Sunday in this year
    3 Monday 1-53 with more than 3 days this year
    4 Sunday 0-53 with more than 3 days this year
    5 Monday 0-53 with a Monday in this year
    6 Sunday 1-53 with more than 3 days this year
    7 Monday 1-53 with a Monday in this year

    A mode value of 3 can be used as of MySQL 4.0.5. Values of 4 and above can be used as of MySQL 4.0.17. 

    mysql> SELECT WEEK('1998-02-20');
        -> 7
mysql> SELECT WEEK('1998-02-20',0);
        -> 7
mysql> SELECT WEEK('1998-02-20',1);
        -> 8
mysql> SELECT WEEK('1998-12-31',1);
        -> 53

    Note: In MySQL 4.0, WEEK(date,0) was changed to match the calendar in the USA. Before that, WEEK() was calculated incorrectly for dates in the USA. (In effect, WEEK(date) and WEEK(date,0) were incorrect for all cases.)

    Note that if a date falls in the last week of the previous year, MySQL returns 0 if you do not use 2, 3, 6, or 7 as the optional mode argument: 

    mysql> SELECT YEAR('2000-01-01'), WEEK('2000-01-01',0);
        -> 2000, 0

    One might argue that MySQL should return 52 for the WEEK() function, because the given date actually occurs in the 52nd week of 1999. We decided to return 0 instead because we want the function to return “the week number in the given year.” This makes use of the WEEK() function reliable when combined with other functions that extract a date part from a date.

    If you would prefer the result to be evaluated with respect to the year that contains the first day of the week for the given date, use 0, 2, 5, or 7 as the optional mode argument. 

    mysql> SELECT WEEK('2000-01-01',2);
        -> 52

    Alternatively, use the YEARWEEK() function: 

    mysql> SELECT YEARWEEK('2000-01-01');
        -> 199952
mysql> SELECT MID(YEARWEEK('2000-01-01'),5,2);
        -> '52'

  • WEEKDAY(date)

    Returns the weekday index for date (0 = Monday, 1 = Tuesday, … 6 = Sunday). 

    mysql> SELECT WEEKDAY('1998-02-03 22:23:00');
        -> 1
mysql> SELECT WEEKDAY('1997-11-05');
        -> 2

  • WEEKOFYEAR(date)

    Returns the calendar week of the date as a number in the range from 1 to 53. WEEKOFYEAR() is a compatibility function that is equivalent to WEEK(date,3). 

    mysql> SELECT WEEKOFYEAR('1998-02-20');
        -> 8

    WEEKOFYEAR() is available as of MySQL 4.1.1.

  • YEAR(date)

    Returns the year for date, in the range 1000 to 9999, or 0 for the “zero” date. 

    mysql> SELECT YEAR('98-02-03');
        -> 1998

  • YEARWEEK(date), YEARWEEK(date,mode)

    Returns year and week for a date. The mode argument works exactly like the mode argument to WEEK(). The year in the result may be different from the year in the date argument for the first and the last week of the year. 

    mysql> SELECT YEARWEEK('1987-01-01');
        -> 198653

    Note that the week number is different from what the WEEK() function would return (0) for optional arguments 0 or 1, as WEEK() then returns the week in the context of the given year.

    YEARWEEK() was added in MySQL 3.23.8.


User Comments

Posted by Isaac Shepard on October 11 2003 2:53pm[Delete] [Edit]

If you're looking for generic SQL queries that will allow you to get the days, months, and years between any two given dates, you might consider using these. You just need to substitute date1 and date2 with your date expressions.

NOTE: Some of these formulas are complex because they account for all cases where date1 < date2, date1 = date2, and date1 > date2. Additionally, these formulas can be used in very generic queries where aliases and temporary variables are not allowed.


Number of days between date1 and date2:


TO_DAYS(date2) - TO_DAYS(date1)


Number of months between date1 and date2:


IF((((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) > 0, (((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) - (MID(date2, 9, 2) < MID(date1, 9, 2)), IF((((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) < 0, (((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) + (MID(date1, 9, 2) < MID(date2, 9, 2)), (((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1)))))


Number of years between date1 and date2:


IF((YEAR(date2) - YEAR(date1)) > 0, (YEAR(date2) - YEAR(date1)) - (MID(date2, 6, 5) < MID(date1, 6, 5)), IF((YEAR(date2) - YEAR(date1)) < 0, (YEAR(date2) - YEAR(date1)) + (MID(date1, 6, 5) < MID(date2, 6, 5)), (YEAR(date2) - YEAR(date1))))


Now for some comments about these.


1. These results return integer number of years, months, and days. They are "floored." Thus, 1.4 days would display as 1 day, and 13.9 years would display as 13 years. Likewise, -1.4 years would display as -1 year, and -13.9 months would display as -13 months.


2. Note that I use boolean expressions in many cases. Because boolean expressions evaluate to 0 or 1, I can use them to subtract or add 1 from the total based on a condition.


For example, to calculate the number of years between to dates, first simply subtract the years. The problem is that doing so isn't always correct. Consider the number of years between July 1, 1950 and May 1, 1952. Technically, there is only one full year between them. On July 1, 1952 and later, there will be two years. Therefore, you should subtract one year in case the date hasn't yet reached a full year. This is done by checking the if the second month-day is before the first month-
day. If so, this results in a value of 1, which is subtracted from the total. The IF statements are in the formula because we must add one year when dealing with the dates in the opposite order, and we must not add or subtract anything when the difference of the date years is zero.


3. To get the month-day, I use MID. This is better
than using RIGHT, since it will work for both dates
and datetimes.


4. Unlike many other solutions, these queries should
work with dates prior to 01/01/1970.

Posted by Aurelio Sablone on December 6 2002 8:34am[Delete] [Edit]

In order to get the number of seconds between two
datetime values in a table, you could use the
following: SELECT unix_timestamp(date1) -
unix_timestamp(date2) FROM table_name

Posted by [name withheld] on February 6 2003 4:19pm[Delete] [Edit]

Spent some time trying to work out how to calculate the month start x months ago ( so that I can create historical stats on the fly)

here is what I came up with..

((PERIOD_ADD(EXTRACT(YEAR_MONTH FROM CURDATE()),-6)*100)+1)

this gives you the first day of the month six months before the start of the current month in datetime format

Posted by Adam Tylmad on July 28 2003 10:28pm[Delete] [Edit]

To get the date difference between two date-type columns,
use this formula:

sec_to_time(unix_timestamp(EndDateTime) -
unix_timestamp(StartDateTime))

where StartDateTime and EndDateTime are the two columns

/A

Posted by Filip Wolak on August 4 2003 6:44am[Delete] [Edit]

Several times i have come to a followng date/time problem:
In the table i am storing both date and time information in the datetime column. Querying, I want to receive COUNTed results grouped by date, and not date and time. I came to the easy solution:
SELECT DATE_FORMAT(postdate, '%Y-%m-%d') AS dd, COUNT(id) FROM MyTable GROUP BY dd;

I suppose this solution to be quite slow (date formatting).

Later, i 'upgraded' this query to use the string function:
SELECT substring(postdate, 1,10) AS dd, COUNT(id) FROM MyTable GROUP BY dd;

knowing, that the result is in the fixed format. Works faster.

Posted by Stoyan Stefanov on August 16 2003 8:05pm[Delete] [Edit]

Hope this will help somebody. The way I found to sum time:
SELECT SEC_TO_TIME( SUM( TIME_TO_SEC( `time` ) ) ) AS total_time FROM time_table;


Posted by Gerard Manko on December 17 2003 9:27am[Delete] [Edit]

Comparing Dates when using MS Access and MyODBC

If you are using MS Access and have created Access queries to substitute for views (which are not yet available in mySQL), you can use the following syntax ro perform date comparisons and avoid the dreaded "ODBC -- call failed" error:

Select * from [Task Effort Summary]
Where ((Date() + 0) > CLng([Task Effort Summary].[s_end]))

This particular example retuns tasks that are overdue (where todays date is past the scheduled end date). This query was developed for reports on a TUTOS database.

Posted by [name withheld] on January 9 2004 7:59pm[Delete] [Edit]

Note that the built-in default values for the DATE and DATEFIELD column types is out of range. For example, 0000-00-00 is a valid way of expressing NULL, but if the column is set as NOT NULL, 0000-00-00 is still the default value. This can cause problems with some applications using MySQL.

Posted by [name withheld] on January 27 2004 3:25am[Delete] [Edit]

I was looking for a function to detect if the current week is odd or even. I could not find one so I use this:
MOD((DATE_FORMAT(CURDATE(),"%v")),2)
The output is a '0'(even) or a '1'(odd)

Posted by Steve West on February 15 2004 10:49pm[Delete] [Edit]

To create a DATETIME of NOW() in UTC without upgrading to 4.1.1, just use:

DATE_ADD( '1970-01-01', INTERVAL UNIX_TIMESTAMP() SECOND )

Posted by [name withheld] on March 4 2004 9:39am[Delete] [Edit]

workaround for STR_TO_DATE pre version 4.1.1. ugly but it seems to work fine.

assumption: you know the format of the received date (in the below example the format is mm/dd/yy, m/d/yy, mm/dd/yyyy, etc)

the statement extracts the year by locating the index of the second '/' and reading from the right of the string to that index. the index of the second is '/' is found by using LOCATE with the index of the first '/'.
it extracts the day by locating the indeces of the first and second '/' and reading between them
it extracts the month by locating the index of the first '/' and reading from the left of the string to that index.
it then CONCATs the year month and day pieces together separating them with hyphens.
lastly, it lets DATE_FORMAT do its magic on the string.

(replace the test string '1/11/03' with your field name, etc)

select DATE_FORMAT( CONCAT( RIGHT( '1/11/03' , length( '1/11/03') - LOCATE('/', '1/11/03' , LOCATE('/', '1/11/03' ) + 1 ) ) , '-' , LEFT( '1/11/03' , LOCATE('/', '1/11/03' ) - 1 ) , '-', SUBSTRING( '1/11/03' , LOCATE('/', '1/11/03' ) + 1, LOCATE('/', '1/11/03' , LOCATE('/', '1/11/03' ) + 1 ) - LOCATE('/', '1/11/03' ) - 1 ) ) , '%Y-%m-%d' )

Posted by Olav Alexander Mjelde on March 15 2004 11:15am[Delete] [Edit]

Lets say you have the mysql before 4.1.1 (where timediff() was implementet), and you want to do a timediff.

I wanted to make a "active users" on my page, but I found out that I didnt have the timediff function (to find persons which have been active within 5 minutes).

So, I figured this query out:

SELECT nick FROM `users` WHERE TO_DAYS( NOW( ) ) - TO_DAYS( last_login ) <=1 AND DATE_FORMAT( CURRENT_TIMESTAMP( ) , '%H%i' ) - DATE_FORMAT( last_login, '%H%i' ) <=5 ORDER BY `nick` ASC;

it selects the field nick (which is the only one to be displayd) and then it filters for 1 day or less in age of activity. after that, it filters for 5 minutes or less in activity.

first you need to filter away the other days, or your script might get fooled to think that yesterdays login was todays.

I'm currently using this, and it works fine!
on the other page, you of course need to update the timestamp field (when session excists, on reload)

Posted by Cherice Scharf on April 5 2004 11:24am[Delete] [Edit]

Here is an example to convert various user inputs for a date field on an ASP page (VBScript) that will convert common formats (i.e., m/d/yy, mm/dd/yyyy, etc.) to MySQL database format of (yyyy-mm-dd). The function begins by establishing that there is a date in the field. Then splits the date (converted to string) into three parts by locating "/". DateArray(0), DateArray(1), DateArray(2) hold the month, day and year, respectively. These are then checked for the amount of digits, if there are not enough digits in month or day then a leading zero is added. If there are only two digits on the year (ie "04") then a leading "20" is added.

Function ConvertInputDate(varDate)

If (Len(Trim(varDate)) > 0) Then
DateArray=Split(CStr(varDate),"/")

IF Len(Trim(DateArray(0))) < 2 Then
DateArray(0) = "0" & DateArray(0)
End If

If Len(Trim(DateArray(1))) < 2 Then
DateArray(1) = "0" & DateArray(1)
End If

If Len(Trim(DateArray(2))) < 4 Then DateArray(2) = "20" & DateArray(2)
End If

varDate = DateArray(2) & "-" & DateArray(0) & "-" & DateArray(1)

End If

End Function

*Please note if a user does not use two slashes this function will not work. It is best to indicate "mm/dd/yy" near the label on the page. It will take 4/6/04, 10/6/04, 3/16/2004 and all combinations with two slashes.

Posted by Jason Richard on April 9 2004 7:20am[Delete] [Edit]

I had a problem with my login script using PHP and MySQL when daylight savings time (DST) came around this year.

I was using MYSQL NOW() function to add the current date and time to the user's record into a datetime field. When DST came into effect newly entered login times were an hour slow (I'm in EST). Since the last login is to be updated only if an hour or more has passed since the last login this was a big problem!

The problem is that PHP takes DST into account and MySQL does not (as far as I know) and I was entering the time using MySQL's NOW() function and then comparing the value returned by PHP's time() function.

A very simple solution to this is the following. Note the PHP time format string 'YmdHis' - it formats to YYYYMMDDHHMMSS which is what MySQL expects for a date/time field.

$now = time();
$lastLogin = strtotime($row['lastLogin']);
$diff = $now - $lastLogin;
$now = date('YmdHis',$now)

if($diff > 3600) { // 3600 seconds is 1 hour
$query = 'UPDATE members SET logins = logins + 1, lastLogin = '.$now.' WHERE memberID = '.$SEC_ID;
mysql_query($query);
}

Now the date entered is the PHP time (that accounts for DST) and we are comparing it to PHP time so all is well.

I think this approach will work well for any time you wish to enter a date into MySQL using PHP. Just format the date using the "YmdHis" format string and use the strtotime() function to read a date retrieved from MySQL.

The advantage to this approach rather than just entering the "normal" PHP date into a char or text field is that the dates are "human" readable in the table and all the MySQL date/time functions are available for future queries.

Posted by Martin Schwedes on April 25 2004 9:11am[Delete] [Edit]

to localize the weekday:
SELECT ELT( WEEKDAY('2004-04-10')+1, 'Montag','Dienstag','Mittwoch','Donnerstag','Freitag','Samstag','Sonntag');

long version with month:
SELECT DATE_FORMAT( '2004-04-10', CONCAT( ELT( WEEKDAY('2004-04-10')+1, 'Montag','Dienstag','Mittwoch','Donnerstag','Freitag','Samstag','Sonntag'),', %d. ', ELT( MONTH('2004-04-10'), 'Januar','Februar','März','April','Mai','Juni','Juli','August','September','Oktober','November','Dezember'),' %Y'));
--> Samstag, 10. April 2004

same for unix-timestamp:
SELECT DATE_FORMAT( FROM_UNIXTIME(1081548000), CONCAT( ELT( WEEKDAY(FROM_UNIXTIME(1081548000))+1, 'Mo','Di','Mi','Do','Fr','Sa','So'),', %d. ', ELT( MONTH(FROM_UNIXTIME(1081548000)), 'Jan.','Feb.','März','April','Mai','Juni','Juli','Aug.','Sept.','Okt.','Nov.','Dez.'),' %Y'));
--> Sa, 10. April 2004

Posted by Philippe Poelvoorde on April 30 2004 5:50am[Delete] [Edit]

I had to query a table and retrieve rows that were added only today, so :

select id from my_table
where
timestamp < date_format(date_add(CURRENT_TIMESTAMP(), interval 1 day),'%Y%m%d000000')
AND
timestamp >= date_format(CURRENT_TIMESTAMP(),'%Y%m%d000000')

starting with MySQL 4.0, you could also use the BETWEEN ... AND syntax.
If anyone has a better query to do that, let me know.

Posted by Michael Marcus on May 1 2004 2:41pm[Delete] [Edit]

After reading numerous articles and posts regarding converting back and forth between SQL datetime and VBscript datetime, I opted for the simplest solution for my databases. I simply save all datetime values in varchar(20) fields and call on either MySQL or VBscript functions to get datetime values or check/convert datetime values. For example:

currentDT = CStr(cn.execute("SELECT NOW()").Fields(0).Value)

will fetch current datetime in the SQL server's datetime format and then convert it to a string. [Obviously, cn is set by Set cn = Server.CreateObject("ADODB.Connection") to create the database connection, then the database is opened with a cn.open (parameters).]

You can then save this string to an appropriate field such as 'flddate_added' which is formatted as varchar(20).

When retrieving the flddate_added value, you can use this VBscript code to check if the value is indeed a datetime value and convert it to the datetime format of the user's computer"

if IsDate(flddate_added) then
=CDate(flddate_added) ' convert to user's system format for display using user's codepage
else
=flddate_added ' just display the string
end if

The above methods allow me to get around all of the issues regarding VBscript's datetime display format differences depending on the system local.

Posted by Ray Morris on July 15 2004 4:37pm[Delete] [Edit]

Posted by Filip Wolak:

> Several times i have come to a followng date/time problem:
> In the table i am storing both date and time information in the datetime
> column. Querying, I want to receive COUNTed results grouped by date,
> and not date and time.
...
> SELECT substring(postdate, 1,10) ...

If it's a DATETIME column than substring is not appropriate -
it's logically nonsensical of course, and just happens to work
in some version of MySQL because the DATETIME happens
to be represented by a string in some contexts.
Better would be to treat the DATETIME as a DATETIME
rather than as a string, which will work in future versions
of MYSQL and in other RDMS:
SELECT DATE(postdate) ...


Posted by David Lyon on July 17 2004 4:12pm[Delete] [Edit]

Here is another VB/ASP function for converting Dates from standard to MySQL format. Cherise gave a nice example above, but it has extra complexity due to the use of arrays and also may be proned to user input errors.

The following example will work based on the Localization settings of the server on which it is run. So it shouldn't care whether the date is dd-mm-yyyy, mm/dd/yy, mm/dd/yyyy, m-d-yy, etc. Just make sure you pass it a date value that is formatted compliant to the server's localization. If necessary use VB's CDate(strDateValue) before passing strDateValue to the function.

You can also easily modify this function to do the same for Time values, except you use Hour, Minute, and Second VB functions, and delimit with a colon (:) instead of a dash (-).

Hope this helps!

Function funcMySqlDate(dtmChangeDate)
'CONVERTS LOCALIZED DATE FORMAT (for example: m/d/yy) TO MySQL FORMAT (yyyy-mm-dd)
Dim strTempYear, strTempMonth, strTempDay
strTempYear = Year(dtmChangeDate)
strTempMonth = Month(dtmChangeDate)
strTempDay = Day(dtmChangeDate)

if Len(strTempYear) = 2 then 'Y2K TEST - 1938-2037 - ADJUST AS NECESSARY
if strTempYear >= 38 then
strTempYear = "19" & strTempYear
else
strTempYear = "20" & strTempYear
end if
end if
if strTempMonth < 10 then strTempMonth = "0" & strTempMonth
if strTempDay < 10 then strTempDay = "0" & strTempDay

funcMySqlDate = strTempYear & "-" & strTempMonth & "-" & strTempDay
End Function

Posted by Benjamin Zagel on August 5 2004 12:44pm[Delete] [Edit]

To find out the last day of a month use:

SELECT (DATE_FORMAT('2004-01-20' ,'%Y-%m-01') - INTERVAL 1 DAY) + INTERVAL 1 MONTH;

It tooks me a few time to have this idea, but it works. If you want to have the first day of a month use:

SELECT DATE_FORMAT('2004-01-20' ,'%Y-%m-01');

To find out the first day of a month was my first development step, then it was easy to extract the last day of a month. It is usefull for accounting for services where I need this solution.

Greetings

Posted by Mark Stafford on August 6 2004 5:26pm[Delete] [Edit]

I see the use for both, but I find this layout more useful as a reference tool:

+--------------+----------+--------------------+
| metric       | variant  | result             |
+--------------+----------+--------------------+
| microseconds | %f       | 000000..999999     |
| seconds      | %s or %S | 00..59             |
| minutes      | %i       | 00..59             |
| hours        | %H       | 00...23            |
|              | %h or %I | 00...12            |
|              | %k       | 0...23             |
|              | %l       | 1...12             |
| day          | %a       | Sun...Sat          |
|              | %D       | 1st, 2nd, 3rd      |
|              | %d       | 0.31               |
|              | %e       | 0..31              |
|              | %j       | 001...366          |
|              | %W       | Sunday...Sat       |
|              | %w       | 0...6              |
| week         | %U       | 00...53 per Sun    |
|              | %u       | 00...53 per Mon    |
| *            | %V       | 01...53 per Sun    |
| *            | %v       | 01...53 per Mon    |
| month        | %b       | Jan...Dec          |
|              | %c       | 0...12             |
|              | %M       | January...December |
|              | %m       | 00...12            |
| year         | %Y       | 1999               |
|              | %y       | 99                 |
| *            | %X       | 1999               |
| *            | %x       | 99                 |
| time         | %r       | 01:31:12 pm        |
|              |          | %T | 01:31:12 pm   |
|              | %p       | AM or PM           |
| Percent sign | %%       | %                  |
+--------------+----------+--------------------+



Posted by M l on August 7 2004 6:53pm[Delete] [Edit]

Select records that are older than X days from the current date where sent_time is a Timestamp datatype field.

select ID from MESSAGE where SENT_TIME < (CURDATE() - INTERVAL 5 DAY);

Posted by R C on August 24 2004 7:21pm[Delete] [