SQL Reference

LOOP Statement

The LOOP statement repeats the execution of a statement or a group of statements.

Syntax

                        .-------------------------------.
                        V                               |
>>-+---------+--LOOP-------SQL-procedure-statement--;---+------->
   '-label:--'
 
>----END LOOP----+--------+------------------------------------><
                 '-label--'
 

Description

label

Specifies the label for the LOOP statement. If the beginning label is specified, that label can be specified on LEAVE and ITERATE statements. If the ending label is specified, a matching beginning label must be specified.

SQL-procedure-statement

Specifies the statements to be invoked 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