Question

为了说明，以下是Postgres 9.6中的一些表格：

people
 id | name 
----+------
  1 | a
  2 | b
  3 | c
  4 | d

groups
 id | name 
----+-------
 10 | xxx
 20 | yyy
 30 | zzz

people_in_group
person_id | group_id
----------+-------
1         | 10
2         | 10

我想在people_in_group中插入多个值，并将组名返回给我。我已经有了person_id（2）。以下工作，但不返回名称。

INSERT INTO people_in_group(person_id, group_id) 
  SELECT '2' AS person_id, id as group_id FROM groups 
  WHERE name IN ('xxx', 'yyy', 'not there') 
  ON CONFLICT DO NOTHING 
  RETURNING *;

如果我将name添加到SELECT子句，我将获得INSERT has more expressions than target columns。有没有办法让groups表中的name返回给我（通过RETURNING子句）？我知道我传入了组名，但上面的查询将无法插入'xxx'（重复键），'不存在'（没有这样的组），所以它只会返回'yyy'。理想情况下，我希望能够知道某些INSERTs失败的原因，但我会采取我能得到的结果。

Answer 1

with i as (
    insert into people_in_group(person_id, group_id) 
    select '2' as person_id, id as group_id
    from groups 
    where name in ('xxx', 'yyy', 'not there') 
    on conflict do nothing 
    returning *
)
select i.person_id, i.group_id, g.name
from i inner join groups g on g.id = i.group_id

选择更多列以进行插入以在RETURNING语句中使用

1 个答案: