LOOP statement

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

Invocation

This statement can be embedded in an:

SQL procedure definition
Compound SQL (compiled) statement
Compound SQL (inlined) statement

The compound statements can be embedded in an SQL procedure definition, SQL function definition, or SQL trigger definition. It is not an executable statement and cannot be dynamically prepared.

Authorization

No privileges are required to invoke the LOOP statement. However, the authorization ID of the statement must hold the necessary privileges to invoke the SQL statements that are embedded in the LOOP statement.

Syntax

SQL-routine-statement

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 SQL statements that are to be invoked in the loop. SQL-procedure-statement is only applicable when in the context of an SQL procedure or Compound SQL (compiled) statement. See SQL-procedure-statement in Compound SQL (compiled) statement.

SQL-function-statement

Specifies the SQL statements that are to be invoked in the loop. SQL-function-statement is only applicable when in the context of an SQL function, SQL method, or Compound SQL (inlined) statement. See SQL-function-statement in FOR.

Example

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