選擇從數據庫中唯一記錄

Question

運行此查詢，

select * from table; 

返回以下

|branch | number | 
------------------- 
| 1 | 123 | 
| 1 | 001 | 
| 2 | 123 | 
| 3 | 123 | 
| 4 | 123 | 
| 1 | 123 | 
| 1 | 789 | 
| 2 | 123 | 
| 3 | 123 | 
| 4 | 009 | 

我想找到所獨有的唯一分支機構值1

| 1 | 001 | 
| 1 | 789 | 

可以這樣沒有將數據存儲在單獨的表中？我試過幾個「select distinct」查詢&似乎沒有得到我期待的結果。

Answer 1

我猜我想說的是，我想找到所有僅適用於分支1的數字。如果它們在任何其他分支中找到，我不想看到它們。

我想這就是你想要的。

SELECT distinct number 
FROM MyTable 
WHERE branch=1 and number not in 
(SELECT distinct number 
FROM MyTable 
WHERE branch != 1) 

Answer 2

試試這個：

SELECT branch, number 
FROM table 
GROUP BY branch, number 

這裏是一個SQLFiddle讓你看看

如果你想將其限制在只有1處，則只需添加一個WHERE子句。

SELECT branch, number 
FROM table 
WHERE branch = 1 
GROUP BY branch, number 

Answer 3

SELECT branch, number 
FROM table 
WHERE branch = 1 
GROUP BY branch, number 

Answer 4

如果您不需要任何聚集，可以使用distinct代替group by：

select distinct branch 
,  number 
from YourTable 
where branch = 1 

Answer 5

要選擇在number列獨特的全值，並有1 branch值，可以使用下面的代碼：

SELECT branch, number 
FROM table1 
WHERE number IN (
SELECT number 
FROM table1 
GROUP BY number 
HAVING (COUNT(number) = 1) 
) 
AND branch = 1 

對於一個演示中看到http://sqlfiddle.com/#!2/97145/62