Question

我收到“ERROR 1415（0A000）：更新包含以下触发器的表时，不允许从触发器返回结果集”，但不明白原因。

CREATE TRIGGER my_trigger AFTER UPDATE ON my_triggering_table
FOR EACH ROW CALL my_procedure();

我离开了触发器不能使用返回结果集的SELECT，但是被调用的过程（及其子进程）只使用CURSOR FOR SELECT和FETCH INTO，据我所知，这是允许的。他们读取但不修改触发表。

任何人都可以解释错误吗？（MySQL 5.5）下面的调用程序。

CREATE PROCEDURE my_procedure()
BEGIN
  DECLARE v_mark VARCHAR(4);
  DECLARE v_lat, v_lon DOUBLE;
  DECLARE eof INT DEFAULT FALSE;
  DECLARE my_cursor CURSOR FOR SELECT `mark`, `lat`, `lon` FROM my_triggering_table ORDER BY `order`;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET eof = TRUE;
  DELETE FROM my_output_table;
  OPEN my_cursor;
  loop1: LOOP
    FETCH my_cursor INTO v_mark, v_lat, v_lon;
    IF eof THEN
      LEAVE loop1;
    END IF;
    CALL my_procedure_2(v_mark, v_lat, v_lon);
  END LOOP;
  CLOSE my_cursor;
END//

CREATE PROCEDURE my_procedure_2(IN from_mark VARCHAR(4), IN from_lat DOUBLE, IN from_lon DOUBLE)
BEGIN
  DECLARE v_mark VARCHAR(4);
  DECLARE v_lat, v_lon DOUBLE;
  DECLARE eof INT DEFAULT FALSE;
  DECLARE my_cursor CURSOR FOR SELECT `mark`, `lat`, `lon` FROM my_triggering_table ORDER BY `order`;
  DECLARE CONTINUE HANDLER FOR NOT FOUND SET eof = TRUE;
  OPEN my_cursor;
  loop1: LOOP
    FETCH my_cursor INTO v_mark, v_lat, v_lon;
    IF eof THEN
      LEAVE loop1;
    END IF;
    INSERT INTO my_output_table(`from`, `to`, `dist`, `brg`, `lat`, `lon`)
        VALUES(from_mark
             , v_mark
             , IF(from_mark = v_mark, NULL, getDist(from_lat, from_lon, v_lat, v_lon))
             , IF(from_mark = v_mark, NULL, getBearing(from_lat, from_lon, v_lat, v_lon))
             , coord_dec2ms(from_lat, true)
             , coord_dec2ms(from_lon, false)
              );
  END LOOP;
  CLOSE my_cursor;
END//

调用的UDF不引用任何表。

MySQL：不允许从触发器返回结果集

0 个答案: