我有三张表,父母、子女和孙子:

+----------------+   +----------------+   +---------------------+
| parent         |   | child          |   | grandchild          |
+----------------+   +----------------+   +---------------------+
| parent_id (PK) |   | child_id (PK)  |   | grandchild_id (PK)  |
| parent_data    |   | child_data     |   | grandchild_data     |
+----------------+   | parent_id (FK) |   | child_id (FK)       |
                     +----------------+   +---------------------+

pk=自动递增主键。
FK=外键。
我需要一个存储过程,它可以复制父表中的记录以及子表和孙表中的任何关联记录。我可以复制父母和孩子的数据,这是我正在挣扎的孙子表。就我所知:
CREATE FUNCTION sf_copy_parent(p_parent_id INT) RETURNS INT
BEGIN
    DECLARE new_parent_id INT;

    -- create new parent record
    INSERT INTO parent(parent_data)
        SELECT parent_data FROM parent
        WHERE parent_id=p_parent_id;
    SET new_parent_id=LAST_INSERT_ID();

    -- copy child records
    INSERT INTO child(child_data,parent_id)
        SELECT child_data,new_parent_id FROM child
        WHERE parent_id=p_parent_id;

    -- copy grandchild records ???


    -- return
    RETURN new_parent_id;
END

如果重要的话,我会使用mysql5.5。

最佳答案

尝试此选择查询(它使用'p_parent_id'和'new_parent_id'变量)-

SET @r1 = 1;
SET @child_id = NULL;
SET @r2 = 0;

SELECT c1.grandchild_data, c2.child_id FROM (
  SELECT @r1 := if(c.child_id IS NULL OR c.child_id <> @child_id, @r1 + 1, @r1) rank, @child_id := c.child_id, c.child_id, g.grandchild_data FROM child c
  JOIN grandchild g
    ON c.child_id = g.child_id
  WHERE
    c.parent_id = p_parent_id
  ORDER BY
    c.child_id, g.grandchild_id
  ) c1
JOIN (SELECT @r2 := @r2 + 1 rank, child_id FROM child WHERE parent_id = new_parent_id ORDER BY child_id) c2
  ON c1.rank = c2.rank;

如果有效,我们将重写它以插入..select语句,或者尝试自己执行;)

09-11 19:58