The limit to the number of nested levels depends on available memory. IF tests can be nested after another IF or following an ELSE. When this construct is used in a stored procedure, it is frequently used to test for the existence of some parameter. RemarksĪn IF.ELSE construct can be used in batches, in stored procedures, and in ad hoc queries.
To define a statement block, use the control-of-flow keywords BEGIN and END. Unless a statement block is used, the IF or ELSE condition can affect the performance of only one Transact-SQL statement. Is any Transact-SQL statement or statement grouping as defined by using a statement block. If the Boolean expression contains a SELECT statement, the SELECT statement must be enclosed in parentheses. Is an expression that returns TRUE or FALSE.
To view Transact-SQL syntax for SQL Server 2014 and earlier, see Previous versions documentation.
