Learning PHP, MySQL, JavaScript, and CSS, 2nd Edition

Name

DATE_ADD()

Synopsis

DATE_ADD(date, INTERVAL expr unit)

Returns the result of adding the expression expr using the units unit to the date. The date argument is the starting date or DATETIME value, and expr may start with a - symbol for negative intervals. Table D-1 shows the interval types supported and the expected expr values. Note the examples in this table that show where it is necessary to surround the expr value with quotes for MySQL to interpret them correctly (although, if you are ever in doubt, adding the quotes will always work).

Table D-1. Expected expr values

Type	Expected expr value	Example
MICROSECOND	MICROSECONDS	111111
SECOND	SECONDS	11
MINUTE	MINUTES	11
HOUR	HOURS	11
DAY	DAYS	11
WEEK	WEEKS	11
MONTH	MONTHS	11
QUARTER	QUARTERS	1
YEAR	YEARS	11
SECOND_MICROSECOND	'SECONDS.MICROSECONDS'	11.22
MINUTE_MICROSECOND	'MINUTES.MICROSECONDS'	11.22
MINUTE_SECOND	'MINUTES:SECONDS'	'11:22'
HOUR_MICROSECOND	'HOURS.MICROSECONDS'	11.22
HOUR_SECOND	'HOURS:MINUTES:SECONDS'	'11:22:33'
HOUR_MINUTE	'HOURS:MINUTES'	'11:22'
DAY_MICROSECOND	'DAYS.MICROSECONDS'	11.22
DAY_SECOND	'DAYS HOURS:MINUTES:SECONDS'	'11 22:33:44'
DAY_MINUTE	'DAYS HOURS:MINUTES'	'11 22:33'
DAY_HOUR	'DAYS HOURS'	'11 22'
YEAR_MONTH	'YEARS-MONTHS'	'11-2'

You can also use the DATE_SUB function to subtract date intervals. However, it’s not actually necessary for you to use the DATE_ADD or DATE_SUB functions, as you can use date arithmetic directly in MySQL. This ...