If-unknown ?

Operator: ?

The If-Unknown operator ? checks whether a value is unknown.

If the value is not unknown (it has a specific value), that value is returned. If it is unknown, the second value is returned.

The If-Unknown operator can be used on any WEM-type: all WEM-types can be unknown - so they also can be checked for unknown and in that case the second operand should be used. Both operands must be of the same type.

This function is SQL compatible. For more information about SQL compatibility, see our documentation.

Returns Value1 if it is not unknown. Otherwise Value2 is returned.

value1 ? value2

text ? "Please enter a value" =>If `text` is unknown then the result is "please enter a value". If `text` is not unknown then `text`' is the result.

unknownnumber ? 0 => 0

unknowntext ? "some text" => "some text"

unknownboolean ? false => false

unknowndatetime ? Now() => result of now() - current date and time

unknownconcept ? 'concept1' => 'concept1'

unknownreference ? [CurrentUserRef] => [CurrentUserRef]

"" ? 0 => expression type mismatch