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Predicates

The standard comparators are available:

  • expr1 < expr2 (less than)
  • expr1 <= expr2 (less than or equal to)
  • expr1 > expr2 (greater than)
  • expr1 >= expr2 (greater than or equal to)
  • expr1 = expr2 (equal to)
  • expr1 <> expr2 | expr1 != expr2 (not equal to)

Greatest / Least

Section titled “Greatest / Least”

These aren’t strictly predicates - they return the greatest/least value of their arguments respectively:

GREATEST(expr, ...)
returns the greatest value of the provided arguments, by the usual comparison operators
LEAST(expr, ...)
returns the least value of the provided arguments, by the usual comparison operators

Boolean functions

Section titled “Boolean functions”
expr1 AND expr2
returns true if both expr1 and expr2 are true, false otherwise
expr1 OR expr2
returns true if either expr1 or expr2 are true, false otherwise
NOT expr
returns true if expr is false, false otherwise
expr IS [NOT] TRUE
returns true if expr is [not] true, false otherwise (including if expr is null)
expr IS [NOT] FALSE
returns true if expr is [not] false, false otherwise (including if expr is null)
expr IS [NOT] NULL
returns true if expr is [not] null, false otherwise