如何通過在MySQL

Question

匹配同桌

我在MySQL數據庫 表下表結構來獲取數據：MYTABLE

-------------------------------- 
| uid | locationid | projectid | 
-------------------------------- 
| 2 |  4  | 2  | 
| 2 |  4  | 2  | 
| 2 |  3  | 5  | 
| 2 |  3  | 5  | 
| 2 |  1  | 2  | 
| 2 |  1  | 2  | 
| 2 |  1  | 2  | 
| 2 |  1  | 1  | 
| 3 |  1  | 5  | 
| 3 |  1  | 2  | 
| 3 |  1  | 1  | 
| 3 |  1  | 1  | 
| 7 |  3  | 1  | 
| 5 |  1  | 5  | 
| 6 |  4  | 2  | 
| 5 |  1  | 5  | 
| 3 |  4  | 1  | 
| 3 |  3  | 3  | 
| 7 |  4  | 2  | 
| 7 |  4  | 3  | 

說我傳遞的uid = 2那麼對於UID = 2獨特locationid和專案的組合這個

| 2 |  4  | 2  | 
| 2 |  3  | 5  | 
| 2 |  1  | 2  | 
| 2 |  1  | 1  | 

現在我想要所有具有上述locationid和projectid組合匹配的uid。意味着結果應該是

| 3 |  1  | 2  | 
| 3 |  1  | 1  | 
| 3 |  1  | 1  | 
| 6 |  4  | 2  | 
| 7 |  4  | 2  | 

如果我傳遞的uid = 3，那麼結果應該是

| 2 |  1  | 2  | 
| 2 |  1  | 2  | 
| 2 |  1  | 2  | 
| 2 |  1  | 1  | 
| 5 |  1  | 5  | 
| 5 |  1  | 5  | 

爲此，我使用下面的查詢，但它給出錯誤的結果作爲locationid和專案組合不正確地匹配

SELECT a.* 
FROM Mytable a, Mytable b 
WHERE a.locationid = b.locationid 
AND a.projectid = b.projectid 
AND a.locationid IN (SELECT DISTINCT locationid FROM Mytable WHERE uid=$pmid) 
AND a.projectid IN(SELECT DISTINCT projectid FROM Mytable WHERE uid=$pmid) 
AND a.uid !=$pmid 

這裏$ pmid是我通過的uid值。我的查詢出了什麼問題？我的查詢是否正確？ 請幫幫我。

在此先感謝。

Answer 1

嘗試此查詢 -

SELECT t1.* FROM mytable t1 
    JOIN (SELECT * FROM mytable WHERE uid = 2 GROUP BY locationid, projectid) t2 
    ON t1.uid <> t2.uid AND 
     t1.locationid = t2.locationid AND 
     t1.projectid = t2.projectid; 

指定的WHERE子句中的（第二行）。

Answer 2

這應該工作：

SELECT a.* 
FROM Mytable a 
    INNER JOIN (SELECT DISTINCT locationid, projectid 
       FROM Mytable 
       WHERE uid = 2 
       ) b 
     ON a.locationid = b.locationid 
      AND a.projectid = b.projectid 
      AND a.uid <> 2; 

例子：SQLFiddle

Answer 3

試試這個：

SELECT t.* 
FROM Mytable t 
JOIN 
     (SELECT distinct locationid , projectid 
     FROM Mytable 
     WHERE uid=<uid>)a 
ON  t.locationid =a.locationid 
AND t.projectid=a.projectid 
WHERE t.uid != <uid>