Question

我有三张桌子：

table1（id，name，foo）
  table2（id，name）
  table3（id，id2，name，foo，bar）

我想将table1中的数据复制到表2和表2中。 3，但table3.id2必须对应table2中的行。我想我需要用RETURNING命令做一些事情，但我没有成功。

WITH oldstuff AS (
    SELECT name, foo, 'some value' AS bar
    FROM table1
  ),
  newstuff AS (
    INSERT INTO table2 (name)
    SELECT name FROM oldstuff
    RETURNING id AS id2 /* but i also need oldstuff.name, oldstuff.foo,and oldstuff.bar */
  )
INSERT INTO table3 (id2, name, foo, bar)
SELECT * FROM newstuff; /* I cant just do a join here because the fields arent unique */

Answer 1

从概念上讲，你会这样做：

newstuff

根据您的说法，这并不能完全符合您的要求，因为INSERT INTO table2 (name) SELECT DISTINCT name FROM oldstuff RETURNING *;中没有唯一的名称。为原始表生成唯一ID或仅向其中插入唯一数据：

WITH oldstuff AS (
      SELECT name, foo, 'some value' AS bar
      FROM table1
     ),
     newstuff AS (
      INSERT INTO table2 (name)
          SELECT name
          FROM oldstuff
          RETURNING *
    )
INSERT INTO table3 (id2, name, foo, bar)
    SELECT ns.id, ns.name, os.foo, os.bar
    FROM (SELECT ns.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY name) as seqnum
          FROM newstuff ns
         ) ns JOIN
         (SELECT os.*, ROW_NUMBER() OVER (PARTITION BY name ORDER BY name) as seqnum
          FROM oldstuff os
         ) os
         on ns.name = os.name and ns.seqnum = os.seqnum;

嗯。嗯。。。可能有一种愚蠢的方式：

readvar

这将使用重复的名称，并且您在最终表格中只得到一个匹配。

postgresql：将table1复制到table2和table3，但使用返回的table2值插入table3

1 个答案: