如何运行此查询？

Question

我有下表

MID IID

1   23

1   24

1   25

2   32

2   54

3   11

4   55

5   67

我希望找到所有MID的计数（IID）＆gt; 1 即结果应该是

MID count(IID)

1   3

2   2

P.S - 我试过但是我得到了所有MID的结果。这是我的查询

select distinct a.MID,count(a.IID) from Item_attribute as a group by a.MID

Answer 1

添加如下的子句：

having count(a.IID)>1

Answer 2

在SELECT语句中使用HAVING子句：

SELECT a.MID,count(a.IID) 
FROM Item_attribute as a 
GROUP BY a.MID
HAVING COUNT(a.IID) > 1

Answer 3

请尝试以下方法......

SELECT MID,
       COUNT( IID ) as CountIID
    FROM Item_attribute
    GROUP BY MID
HAVING COUNT( IID ) > 1;

如有其他疑问，请尝试以下操作...

SELECT MID,
       CountIID
FROM
(
    SELECT MID,
           COUNT( IID ) as CountIID
    FROM Item_attribute
    GROUP BY MID
    HAVING COUNT( IID ) > 1
) AS limitedCountIIDFinder
WHERE CountIID =  ( SELECT MAX( CountIID ) AS MaxCountIID
                    FROM
                    (
                        SELECT MID,
                               COUNT( IID ) as CountIID
                        FROM Item_attribute
                        GROUP BY MID
                    ) AS countIIDFinder
                  )

（以下说明......）

如果您有任何问题或意见，请随时发表评论。

Answer 4

如果您希望在聚合字段中拥有条件，则需要使用having 如果您使用group by，也不需要使用distinct 在你的情况下：

select a.MID,count(a.IID) from Item_attribute as a group by a.MID having count(a.IID)>1 

如果您想获得最大计数值，请按降序排序并获得前1：

select top 1 a.MID,count(a.IID) 
from Item_attribute as a 
group by a.MID 
having count(a.IID)>1 
order by count(a.IID) desc