MySQL的選擇唯一行

Question

我有如下表 - mytable：

----id----|----user_id----|----value-----| 
----1-------------1------------- 9 
----2-------------1------------- 8 
----3-------------2 -------------11 
----4-------------2-------------12 
----5-------------3-------------11 
----6-------------4-------------8 
----7-------------1-------------3 

我想SELECT * FROM mytable...其中value有這樣一條記錄：

----id----|----user_id----|----value----- 
----1-------------1-------------9 
----4-------------2-------------12 
----7-------------1-------------3 

注意，值8和值11有重複和我刪除所有

Answer 1

試試這個

SELECT * FROM mytable 
GROUP BY `value` 
HAVING count(*) = 1 

或

SELECT * FROM mytable 
GROUP BY `value` 
HAVING count(*) < 2 

Answer 2

你可以嘗試左連接：

SELECT T1.id, T1.user_id, T1.value 
FROM yourtable T1 
LEFT JOIN yourtable T2 
ON T1.value = T2.value 
AND T1.id <> T2.id 
WHERE T2.id IS NULL 

Answer 3

下面的查詢應該可以正常工作上面提出的問題..

SELECT * T1從 T1 MYTABLE。 ， （ SELECT VALUE FROM MYTABLE GROUP BY VALUE HAVING COUNT（*）= 1 ）T2 WHERE T1.VALUE = T2.VALUE;

問候， Venk

Answer 4

我這樣做：

select t1.* 
from table1 t1 
where 1 = (select count(t2.id) 
        from table1 t2 
        where t1.value = t2.value 
        ) 

希望工程。

PS：ID必須是唯一的關鍵。