IF statements provide conditional execution based on the value of a condition. The IF . . . THEN . . . ELSE . . . END IF construct controls flow based on which of two statement blocks will be executed. You may also use the IF . . . ELSE syntax.
You may use IF statements in the body of both stored procedures and triggers.
There is no limit to the number of nested IF statements allowed, although the query remains subject to the usual total length limitation and other applicable limitations.
Note You cannot use a mixed syntax containing Zen and T.SQL. You may use either the IF...THEN...ELSE...END IF syntax or the IF…ELSE syntax.
If you are using multiple statements with IF or ELSE conditions, you must use BEGIN and END to indicate the beginning and ending of the statement blocks.
Examples
The following example uses the IF statement to set the variable Negative to either 1 or 0, depending on whether the value of vInteger is positive or negative.
IF (:vInteger < 0) THEN
SET :Negative = '1';
ELSE
SET :Negative = '0';
END IF;
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The following example uses the IF statement to test the loop for a defined condition (SQLSTATE = '02000'). If it meets this condition, then the WHILE loop is terminated.