MySql
Date Function
CURDATE() |CURRENT_DATE| CURRENT_DATE()
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.
SELECT CURDATE(); // '2008-06-13' SELECT CURDATE() + 0; // 20080613
CURTIME() |CURRENT_TIME|CURRENT_TIME()
Returns the current time as a value in 'HH:MM:SS' or HHMMSS.uuuuuu format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone.
SELECT CURTIME(); // '23:50:26' SELECT CURTIME() + 0;// 235026.000000
NOW()
Returns the current date and time as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS.uuuuuu format, depending on whether the function is used in a string or numeric context. The value is expressed in the current time zone.
SELECT NOW(); // '2007-12-15 23:50:26' SELECT NOW() + 0;// 20071215235026.000000
DATE(expr)
Extracts the date part of the date or datetime expression expr.
SELECT DATE('2003-12-31 01:02:03'); // '2003-12-31'
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.
SELECT DATEDIFF('2007-12-31 23:59:59','2007-12-30');// 1
SELECT DATEDIFF('2010-11-30 23:59:59','2010-12-31');// -31
DATE_FORMAT(date,format)
Formats the date value according to the format string. The "%" character is required before format . Some of useful specifiers may be used in the format string as follows.
| Specifier | Description | %a | Abbreviated weekday name |
|---|---|
| %b | Abbreviated month name |
| %c | Month, numeric |
| %D | Day of month with English suffix |
| %d | Day of month, numeric (00-31) |
| %e | Day of month, numeric (0-31) |
| %f | Microseconds |
| %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 |
| %m | Month, numeric (00-12) |
| %p | AM or PM |
| %r | Time, 12-hour (hh:mm:ss 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 week |
| %u | Week (00-53) where Monday is the first day of week |
| %V | Week (01-53) where Sunday is the first day of week, used with %X |
| %v | Week (01-53) where Monday is the first day of week, used with %x |
| %W | Weekday name |
| %w | Day of the week (0=Sunday, 6=Saturday) |
| %X | Year of the week where Sunday is the first day of week, four digits, used with %V |
| %x | Year of the week where Monday is the first day of week, four digits, used with %v |
| %Y | Year, four digits |
| %y | Year, two digits |
SELECT DATE_FORMAT('2009-10-04 22:23:00', '%W %M %Y');
// 'Sunday October 2009'
SELECT DATE_FORMAT('2007-10-04 22:23:00', '%H:%i:%s');
// '22:23:00'
SELECT DATE_FORMAT('1900-10-04 22:23:00', '%D %y %a %d %m %b %j');
// '4th 00 Thu 04 10 Oct 277'
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'
SELECT DATE_FORMAT('1999-01-01', '%X %V');
// '1998 52'
UNIX_TIMESTAMP()
Returns a Unix timestamp (seconds since '1970-01-01 00:00:00' GMT)
SELECT UNIX_TIMESTAMP(); // 882226357
SELECT UNIX_TIMESTAMP('2007-11-30 10:30:19'); // 1196440219
STR_TO_DATE(str,format)
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. If the date, time, or datetime value extracted from str is illegal, STR_TO_DATE() returns NULL.
SELECT STR_TO_DATE('01,5,2013','%d,%m,%Y'); // '2013-05-01'
SELECT STR_TO_DATE('a09:30:17','a%h:%i:%s'); // '09:30:17'
SELECT STR_TO_DATE('a09:30:17','%h:%i:%s'); // NULL