從表中選擇計數所需的Sql查詢

Question

我有一個包含以下字段的表。

Col A Col B 
----- ----- 
I1  10 
I1  10 
I2  16 
I3  14 
I2  16 

我需要一個查詢，應按如下給出輸出：

ColA Col B Count 
---- ----- ----- 
I1  10  2 
I2  16  2 
I3  14  1 

如何寫這個查詢。 請幫助

Answer 1

如果ColB總是對的ColA一個特定的值相同，則可以使用max：

select ColA 
,  max(ColB) 
,  count(*) 
from YourTable 
group by 
     ColA 

否則，你不得不解釋如何在你的結果ColB值計算。

Answer 2

請試試這個，讓我知道

select [Col A] ,[Col B] ,count(*) [Count] 
    from <table> 
    group by [Col A] ,[Col B] 
    order by [Col A] 

Answer 3

您可以使用此解決方案：

SELECT ColA, ColB, COUNT(1) AS Count 
FROM tbl 
GROUP BY ColA, ColB 

Answer 4

select colA, colB, count(colB) as `Count` 
from your_table 
group by colA, colB 

Answer 5

SELECT ColA, ColB, Count(ColB) FROM T GROUP BY ColA, ColB 

Answer 6

使用GROUP BY

SELECT colA, colB, COUNT(colB) as Total 
    FROM tableName 
    GROUP BY colA, colB 

Answer 7

試試這個：

SELECT ColA, colB, COUNT(colB) AS Count 
FROM TableName 
GROUP BY ColA,ColB 
ORDER BY ColA,ColB 

見this SQL fiddle.