Boolean

Retrieves rows where the value of an expression is true, false, or unknown (NULL).

Retrieves rows where the value of an expression is true, false, or unknown (NULL).

Syntax

expression IS [NOT] TRUE
expression IS [NOT] FALSE
expression IS [NOT] UNKNOWN

Notes

  • NULL input is treated as the value UNKNOWN.
  • IS UNKNOWN and IS NOT UNKNOWN are effectively the same as the NULL predicate, except that the input expression does not have to be a single column value. To check a single column value for NULL, use the NULL predicate.
  • Do not confuse the Boolean predicate with Boolean operators or the Boolean data type, which can have only two values: true and false.