COALESCE( expression, expression [ , ...] )

The return type for this function depends on the expressions specified. That is, when the database server evaluates the function, it first searches for a data type in which all the expressions can be compared. When found, the database server compares the expressions and then returns the result in the type used for the comparison. If the database server cannot find a common comparison type, an error is returned.

The result is NULL only if all the arguments are NULL.

The parameters can be of any scalar type, but not necessarily same type.

For a more detailed description of how the database server processes this function, see ISNULL function [Miscellaneous].

• ISNULL function [Miscellaneous]

The following statement returns the value 34.

SELECT COALESCE( NULL, 34, 13, 0 );