在 mysql 中查找多個字段的相同記錄

Question

CREATE TABLE IF NOT EXISTS `userinfo` (
  `user_id` int(6) unsigned NOT NULL,
  `user_code` varchar(20),
  `party1_id` varchar(200),
  `party2_id` varchar(200),
  PRIMARY KEY (`user_id`)
) DEFAULT CHARSET=utf8;
INSERT INTO `userinfo` (`user_id`, `user_code`, `party1_id`, `party2_id`) VALUES
  ('1', '05B29E57', '1', ''),
  ('2', '05B29E58', NULL, '1'),
  ('3', '05B29E59', '2', ''),
  ('4', '05B29E60', NULL, '2'),
  ('5', '05B29E61', '3',''),
  ('6', '05B29E62', NULL, '3'),
  ('7', '05B29E63', NULL, '4'),
  ('8', '05B29E64', NULL, '5'),
  ('9', '05B29E65', NULL, '6'),
  ('10', '05B29E66', NULL, '7');

+---------+-----------+-----------+-----------+
| user_id | user_code | party1_id | party2_id |
+---------+-----------+-----------+-----------+
|       1 | 05B29E57  | 1         |           |
|       2 | 05B29E58  | NULL      |         1 |
|       3 | 05B29E59  | 2         |           |
|       4 | 05B29E60  | NULL      |         2 |
|       5 | 05B29E61  | 3         |           |
|       6 | 05B29E62  | NULL      |         3 |
|       7 | 05B29E63  | NULL      |         4 |
|       8 | 05B29E64  | NULL      |         5 |
|       9 | 05B29E65  | NULL      |         6 |
|      10 | 05B29E66  | NULL      |         7 |
+---------+-----------+-----------+-----------+

所以我有上表作為userinfo 。 由於某種原因，我必須找到party1_id 和party2_id 的重復記錄。

我在下面嘗試過：

SELECT
  *
FROM userinfo u1
  JOIN userinfo u2
    ON u1.party1_id = u2.party2_id
WHERE IFNULL(u1.party1_id, 0) > 0
AND IFNULL(u1.party2_id, '') = ''

小提琴： http://sqlfiddle.com/#!9/725eff/1

但它並沒有以我想要的方式給出結果，它只返回 3 條記錄。 有沒有辦法歸檔我預期的 output，排序與我預期的 output 相同。

預期 Output：

+---------+-----------+-----------+-----------+
| user_id | user_code | party1_id | party2_id |
+---------+-----------+-----------+-----------+
|       1 | 05B29E57  | 1         |           |
|       2 | 05B29E58  | NULL      |         1 |
|       3 | 05B29E59  | 2         |           |
|       4 | 05B29E60  | NULL      |         2 |
|       5 | 05B29E61  | 3         |           |
|       6 | 05B29E62  | NULL      |         3 |
+---------+-----------+-----------+-----------+

Answer 1

您可以使用 union 獲得預期的結果

select t1.* 
from userinfo t1
inner join  (
    select a.party1_id apid, b.party2_id bpid
     FROM userinfo a
      JOIN userinfo b
        ON a.party1_id = b.party2_id
) t2 on t2.apid = t1.party1_id
UNION 
select t1.* 
from userinfo t1
inner join  (
    select a.party1_id apid, b.party2_id bpid
     FROM userinfo a
      JOIN userinfo b
        ON a.party1_id = b.party2_id
) t2 on t2.apid = t1.party2_id
order by user_id 

http://sqlfiddle.com/#!9/725eff/17

為了性能，請確保您至少有這些索引

idx1  table userinfo columns (party1_id, party2_id)

idx2 table userinfo columns (party2_id, party1_id)

Answer 2

您可以嘗試以下。

select * from userinfo where 
party1_id  in (
  SELECT
  u1.party1_id
FROM userinfo u1
  JOIN userinfo u2
    ON u1.party1_id = u2.party2_id
WHERE IsNULL(u1.party1_id, 0) > 0
AND IsNULL(u1.party2_id, '') = '') or party2_id in ( SELECT
  u1.party1_id
FROM userinfo u1
  JOIN userinfo u2
    ON u1.party1_id = u2.party2_id
WHERE IsNULL(u1.party1_id, 0) > 0
AND IsNULL(u1.party2_id, '') = '')

Answer 3

嘗試以下查詢：

SELECT
  *
FROM userinfo u1
  where
  u1.party1_id in (select distinct u2.party2_id from userinfo u2) 
  or 
  u1.party2_id in (select distinct u3.party1_id from userinfo u3)

下面是 output 我在你的小提琴上面查詢：（order by 可以應用於任何列）

user_id     user_code   party1_id   party2_id
1           05B29E57    1   
2           05B29E58    (null)      1
3           05B29E59    2   
4           05B29E60    (null)      2
5           05B29E61    3   
6           05B29E62    (null)      3