如何获取两个值都可以在两列中的行？

Question

我有一个table

-- Table Definition ----------------------------------------------

CREATE TABLE rooms (
    id integer GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    user_id_one uuid NOT NULL REFERENCES users(user_id) ON DELETE CASCADE,
    user_id_two uuid NOT NULL REFERENCES users(user_id) ON DELETE CASCADE,
    create_time timestamp with time zone NOT NULL DEFAULT now()
);

-- Indices -------------------------------------------------------

CREATE UNIQUE INDEX room_pkey ON rooms(id int4_ops);

我想用一对特定的 user_id 得到 rooms.id。

执行此操作的最佳方法是什么？

1.

SELECT r.id
FROM rooms r
WHERE '9af0521d-f999-42e8-aafd-4bf2d839eafb' in (user_id_one, user_id_two)
  AND '0ff77b22-62f9-44ce-8f2e-7e85726dbb3e' in (user_id_one, user_id_two)

SELECT r.id
FROM rooms r
WHERE user_id_one in ('9af0521d-f999-42e8-aafd-4bf2d839eafb', '0ff77b22-62f9-44ce-8f2e-7e85726dbb3e')
  AND user_id_two in ('9af0521d-f999-42e8-aafd-4bf2d839eafb', '0ff77b22-62f9-44ce-8f2e-7e85726dbb3e')

SELECT r.id
FROM rooms r
WHERE (
              (user_id_one = '9af0521d-f999-42e8-aafd-4bf2d839eafb'
                  AND user_id_two = '0ff77b22-62f9-44ce-8f2e-7e85726dbb3e')
              OR
              (user_id_one = '0ff77b22-62f9-44ce-8f2e-7e85726dbb3e'
                  AND user_id_two = '9af0521d-f999-42e8-aafd-4bf2d839eafb')
          )

或者完全不同的东西？

Answer 1

假设这两个用户 ID 永远不会有相同的值，那么您的所有三个版本都是有效的。我可以建议另一个版本，也许比您已有的版本更简洁：

SELECT id
FROM rooms r
WHERE LEAST(user_id_one, user_id_two)    = '0ff77b22-62f9-44ce-8f2e-7e85726dbb3e' AND
      GREATEST(user_id_one, user_id_two) = '9af0521d-f999-42e8-aafd-4bf2d839eafb';

上面least/greatest的做法是一箭双雕。无论匹配的 ID 集以何种顺序出现，上述方法都有效，因为它断言较小的 UUID 显示为一个用户 ID，较大的 UUID 显示为另一个用户 ID。

Answer 2

您可以通过数组进行比较：

WHERE ARRAY [user_id_one,user_id_two] @> ARRAY ['9af0521d-f999-42e8-aafd-4bf2d839eafb','0ff77b22-62f9-44ce-8f2e-7e85726dbb3e']

这里是 dbfiddle 示例

Answer 3

我会更改您的第二个查询，以便您只传递一次您想要的一对 uuid：

SELECT id
FROM rooms 
WHERE (?, ?) IN ((user_id_one, user_id_two), (user_id_two, user_id_one));

如何获取两个值都可以在两列中的行？

How to get row where both values could be in two columns?

sql

postgresql