IsNull functions in MS SQL Server

One, ISNULL syntax format ISNULL (check_expression, Replacement_value)

Ii. Introduction to 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.

The return value returns the same type as check_expression. If Check_expression is not NULL, the value of the expression is returned, otherwise Replacement_value is returned.

Instance:

IsNull functions in MS SQL Server