MySQL:

WHILE

Syntax:
[begin_label:] WHILE search_condition DO
statement_list
END WHILE [end_label]

The statement list within a WHILE statement is repeated as long as the
search_condition expression is true. statement_list consists of one or
more SQL statements, each terminated by a semicolon (;) statement
delimiter.

A WHILE statement can be labeled. For the rules regarding label use,
see [HELP labels].

URL: https://dev.mysql.com/doc/refman/8.0/en/while.html

Example

CREATE PROCEDURE dowhile()
BEGIN
DECLARE v1 INT DEFAULT 5;

WHILE v1 > 0 DO
...
SET v1 = v1 - 1;
END WHILE;
END;