mysql存储过程游标嵌套

DELIMITER //

CREATE PROCEDURE NestedCursorExample()
BEGIN
    DECLARE done INT DEFAULT FALSE;
    DECLARE outer_id INT;
    DECLARE outer_name VARCHAR(255);
    DECLARE inner_id INT;
    DECLARE inner_name VARCHAR(255);
    DECLARE cur_outer CURSOR FOR SELECT id, name FROM outer_table;
    DECLARE cur_inner CURSOR FOR SELECT id, name FROM inner_table WHERE parent_id = outer_id;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur_outer;

    read_outer: LOOP
        FETCH cur_outer INTO outer_id, outer_name;
        IF done THEN
            LEAVE read_outer;
        END IF;

        OPEN cur_inner;

        read_inner: LOOP
            FETCH cur_inner INTO inner_id, inner_name;
            IF done THEN
                LEAVE read_inner;
            END IF;

            -- 处理内层数据
            SELECT CONCAT('Outer ID: ', outer_id, ', Outer Name: ', outer_name, ', Inner ID: ', inner_id, ', Inner Name: ', inner_name);

        END LOOP read_inner;

        CLOSE cur_inner;
    END LOOP read_outer;

    CLOSE cur_outer;
END //

DELIMITER ;