mysql存过游标嵌套

DELIMITER //

CREATE PROCEDURE process_data()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE v_id INT;
    DECLARE v_name VARCHAR(255);
    DECLARE cur1 CURSOR FOR SELECT id, name FROM table1;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur1;

    read_loop: LOOP
        FETCH cur1 INTO v_id, v_name;
        IF done THEN
            LEAVE read_loop;
        END IF;

        -- 嵌套游标
        DECLARE cur2 CURSOR FOR SELECT id, value FROM table2 WHERE table1_id = v_id;
        DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

        OPEN cur2;

        nested_loop: LOOP
            FETCH cur2 INTO v_id, v_name;
            IF done THEN
                LEAVE nested_loop;
            END IF;

            -- 处理嵌套游标的数据
            SELECT v_id, v_name;
        END LOOP;

        CLOSE cur2;
    END LOOP;

    CLOSE cur1;
END //

DELIMITER ;

CALL process_data();