SQL ISNULL () function

ISNULL
Replaces NULL with the specified replacement value

Grammar
ISNULL (Check_expression, Replacement_value)

Parameters
Check_expression

An expression that will be checked for null. Check_expression can be of any type.

Replacement_value

The expression that will be returned when check_expression is null. Replacement_value must have the same type as check_expresssion.

return type
Returns the same type as check_expression.

Notes
Returns the value of the expression if check_expression is not NULL, otherwise returns Replacement_value

SQL ISNULL () function