Syntax
------ 
ITERATE label
 
ITERATE can appear only within LOOP, REPEAT, and WHILE
statements.
ITERATE means "do the loop again", and uses the
statement's label to determine which statements to repeat.
The label must be in the same stored program, not in a
caller procedure.
 
If you try to use ITERATE with a non-existing label, or if
the label is associated to a construct which is not a loop,
the following error will be produced:
 
ERROR 1308 (42000): ITERATE with no matching label: 
 
Below is an example of how ITERATE might be used:
 
CREATE PROCEDURE doiterate(p1 INT)
BEGIN
 label1: LOOP
 SET p1 = p1 + 1;
 
 IF p1 

URL: https://mariadb.com/kb/en/iterate/