mysql 游标嵌套

DELIMITER //

CREATE PROCEDURE nested_cursor_example()
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 cur2 CURSOR FOR SELECT id, description FROM table2;

    OPEN cur1;

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

        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 CONCAT('Table1: ', v_name, ' Table2: ', v_name);
        END LOOP;
        CLOSE cur2;
    END LOOP;

    CLOSE cur1;
END //

DELIMITER ;

CALL nested_cursor_example();