Stored procedure to migrate some meta fields to mapped ACF fields

update_postmeta_loop.sql

DROP PROCEDURE IF EXISTS STEPBYSTEP;
DELIMITER ;;

CREATE PROCEDURE STEPBYSTEP()
BEGIN
	DECLARE done INT DEFAULT FALSE;
	DECLARE POST_ID INT DEFAULT 0;
	DECLARE cursor_results CURSOR FOR SELECT ID FROM wp_posts WHERE post_type = 'press_materials';
	DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
	OPEN cursor_results;
    read_loop: LOOP
    	FETCH cursor_results INTO POST_ID;
        IF done THEN
          LEAVE read_loop;
        END IF;
		INSERT INTO `wp_postmeta` (`post_id`, `meta_key`, `meta_value`)
		VALUES
			(POST_ID, '_youtube_link', 'field_5bb647ff03065'),
			(POST_ID, '_credits', 'field_5bb6482903066'),
			(POST_ID, '_year', 'field_5bb6483503067'),
			(POST_ID, '_embed_code', 'field_5bb6484103068'),
			(POST_ID, '_download_link', 'field_5bb6484d03069'),
			(POST_ID, '_thumbnail', 'field_5bb648540306a');
    END LOOP;
    CLOSE cursor_results;
END;
;;

DELIMITER ;

CALL STEPBYSTEP();