DATEADD()

Available in: DSQL, PSQL

Added in: 2.1

Changed in: 2.5

Description: Adds the specified number of years, months, weeks, days, hours, minutes, seconds or milliseconds to a date/time value. (The WEEK unit is new in 2.5.)

Result type: DATE, TIME or TIMESTAMP

Syntax:

DATEADD (<args>)

<args>      ::=  <amount> <unit> TO <datetime>
                 | <unit>, <amount>, <datetime>

<amount>    ::=  an integer expression (negative to subtract)
<unit>      ::=  YEAR | MONTH | WEEK | DAY
                   | HOUR | MINUTE | SECOND | MILLISECOND
<datetime>  ::=  a DATE, TIME or TIMESTAMP expression
The result type is determined by the third argument.

With TIMESTAMP and DATE arguments, all units can be used. (Prior to Firebird 2.5, units smaller than DAY were disallowed for DATEs.)

With TIME arguments, only HOUR, MINUTE, SECOND and MILLISECOND can be used.

Examples:

dateadd (28 day to current_date)
dateadd (-6 hour to current_time)
dateadd (month, 9, DateOfConception)
dateadd (-38 week to DateOfBirth)
dateadd (minute, 90, time 'now')
dateadd (? year to date '11-Sep-1973')