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Controls conditional execution of a SQL statement, as an alternative to the Watcom SQL IF statement.
IF expression statement [ ELSE [ IF expression ] statement ]
The Transact-SQL IF conditional and the ELSE conditional each control the execution of only a single SQL statement or compound statement (between the keywords BEGIN and END).
In comparison to the Watcom SQL IF statement, there is no THEN in the Transact-SQL IF statement. The Transact-SQL version also has no ELSEIF or END IF keywords.
Not in the standard.
The following example illustrates the use of the Transact-SQL IF statement:
IF (SELECT max(ID) FROM sysobjects) < 100 RETURN ELSE BEGIN PRINT 'These are the user-created objects' SELECT name, type, ID FROM sysobjects WHERE ID < 100 END
The following two statement blocks illustrate Transact-SQL and Watcom SQL compatibility:
/* Transact-SQL IF statement */ IF @v1 = 0 PRINT '0' ELSE IF @v1 = 1 PRINT '1' ELSE PRINT 'other' /* Watcom SQL IF statement */ IF v1 = 0 THEN PRINT '0' ELSEIF v1 = 1 THEN PRINT '1' ELSE PRINT 'other' END IF