IS UNKNOWN Predicate

Tests for an unknown value.

Syntax

expression IS [NOT] UNKNOWN

Arguments

expression

specifies any valid SQL expression.

See <sql-expression>
FedSQL Expressions

Details

IS UNKNOWN is a predicate that tests for an unknown value. IS UNKNOWN is used in the WHERE, ON, and HAVING clauses. The IS UNKNOWN predicate resolves to true if the result of the SQL expression is unknown and resolves to false if it is a valid value.

See Also

<search-condition> in the SELECT Statement
Last updated: February 23, 2017