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 ending label is specified, it must be the same as the beginning label. The label name cannot be the same as 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