id="loopstmt">LOOP statement
The LOOP statement repeats the execution of a statement or a group of statements.
Syntax
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.-----------------------------. V | >>-+--------+--LOOP----SQL-procedure-statement-- ;-+------------> '-label:-' >--END LOOP--+-------+----------------------------------------->< '-label-'
Description
- label
- Specifies the label for the LOOP statement. If the ending label is specified, it must be the same as the beginning label. The label name cannot be the same as the routine name or another label within the same scope. For more information, see Labels.
- SQL-procedure statement
- Specifies an SQL statement to be executed in the loop
Examples
This procedure uses a LOOP statement to fetch values from the employee table. Each time the loop iterates, the OUT parameter counter is incremented and the value of v_midinit is checked to ensure that the value is not a single space (' '). If v_midinit is a single space, the LEAVE statement passes the flow of control outside of the loop.
CREATE PROCEDURE LOOP_UNTIL_SPACE (OUT COUNTER INTEGER) LANGUAGE SQL BEGIN DECLARE v_counter INTEGER DEFAULT 0; DECLARE v_firstnme VARCHAR(12); DECLARE v_midinit CHAR(1); DECLARE v_lastname VARCHAR(15); DECLARE c1 CURSOR FOR SELECT firstnme, midinit, lastname FROM employee; DECLARE CONTINUE HANDLER FOR NOT FOUND SET counter = -1; OPEN c1; fetch_loop: LOOP FETCH c1 INTO v_firstnme, v_midinit, v_lastname; IF v_midinit = ' ' THEN LEAVE fetch_loop; END IF; SET v_counter = v_counter + 1; END LOOP fetch_loop; SET counter = v_counter; CLOSE c1; END
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