Question

我有一张表Retail

CustomerID       Itemset
    1              31
    1              30 
    1              78
    2              31
    2              91
    3              30
    3              31

我想找到同时CustomerID和30的{{1}}的计数。 31中的Itemset。即在这种情况下1＆amp; 3，因此计数为2。

我尝试使用&运算符制定查询，但查询并未返回正确答案。

我的查询 - Select count(customerID) from Retail where Itemset=30 & 31

Answer 1

select count(*)
from
(
    select CustomerId
    from Retail
    where Itemset in (30,31)
    group by CustomerId
    having count(distinct Itemset) = 2   -- this guarantees that CustomerId have at least one 30 and at least one 31 in column Itemset 
) T

Answer 2

Select count(distinct(CustomerID))  from (
    select r30.CustomerID
    from Retail r30
    inner join Retail r31 on
    r31.CustomerID = r30.CustomerID
    where 
    r30.Itemset = 30 
    and r31.Itemset = 31
) T

Answer 3

你只想计算不同的CustomerID ......我没有测试过这个，但是相信这是要走的路......

Select count( distinct customerID)
from Retail
where Itemset in (30,31)

---这是错的......经过一点点的修补，我来到了已经提供的解决方案......请不要理会......

 Select count(*)
 from (
       Select CustomerID
       from Retail
       where Itemset in (30,31)
       group by CustomerID
       having count(CustomerID = 2)
  ) T

---荣誉。这假设CustomerID和Itemset不能有重复项。换句话说，它假定您不会有两行或更多行，而CustomerID和Itemset为1,30。

Answer 4

试试这个..

select CustomerID,count(*)  from [dbo].[Retail] where Itemset in(30,31)
group by CustomerID

如果您只想要计数结果，请使用Common Table Expression

像这样：

;with cte1
as
(select CustomerID,count(*) as rs  from [dbo].[Retail] where Itemset in(30,31)
    group by CustomerID
)
select rs from cte1

如何制定这个SQL查询

4 个答案: