2.2.12.3.1.4 Literal Predicate

The literal predicate MUST be true if a given property stands in a given relation to a given literal. The basic syntax is as follows:

 …property operator literal…

The operator MUST be one of the following:

Operator

Description

=

equal to

!= or <>

not equal to

>

greater than

>=

greater or equal to

<

less than

<=

less than or equal to

The literal is simply a value. The type of the value MUST match the type of the property. As a special case, properties that store dates can be compared to a time calculated from the current time. The function that does this is the DATEADD function.

The basic syntax for the DATEADD function is as follows:

 DATEADD(unit, offset, time)

The time in the DATEADD function MUST be another DATEADD function or the GETGMTDATE function, which returns the current date and time. It MUST NOT be a date literal. The offset MUST be a negative integer that specifies how much time to add to the specified time. Because this integer MUST be negative, the DATEADD function actually performs a subtraction. Finally, the first parameter specifies the unit that the second parameter is measured in. Possible values are as follows:

  • YEAR

  • QUARTER

  • MONTH

  • WEEK

  • DAY

  • HOUR

  • MINUTE

  • SECOND

For example, the following predicate example:

 …createdDate > DATEADD(YEAR, -1, GETGMTDATE())…

matches all items having a createdDate property lies less than a year in the past.

 literal-predicate      =      identifier *ws operator *ws value
 value      =      literal / dateadd-function
 literal      =      boolean / hex / decimal / float / string / date
 dateadd-function      =      "DATEADD" *ws "(" *ws dateadd-unit *ws "," *ws dateadd-offset *ws "," *ws dateadd-datetime *ws ")"
 dateadd-unit      =      "YEAR" / "QUARTER" / "MONTH" / "WEEK" / "DAY" / "HOUR" / "MINUTE" / "SECOND"
 dateadd-offset      =      negative-decimal / negative-hex
 dateadd-datetime      =      dateadd-function / "GETGMTDATE()"