SQL使用case语句

Question

I'm trying to group all activity where the count is less than 5 (for data sharing reasons).

The ID Code and ID Name give me high level numbers, but as soon as I include "shop code" I get some low level numbers for customers that go to odd shops once or twice.

Select  Count(*) [Activity],
        T.[ID Code],
        T.[ID Name],
        Case when Count(*) < 6 then 'Other Shop' Else T.Shop End [Shop Code]
From    MyTable T
Group By T.[ID Code],
         T.[ID Name],
         Case when Count(*) < 6 then 'Other Shop' Else T.Shop End

But obviously I can't use a count in a case statement. I've tried some of the solutions to similar questions but none of them work!

Thanks

Answer 1

The problem is the GROUP BY :

Select  Count(*) as [Activity],
        T.[ID Code],
        T.[ID Name],
        (Case when Count(*) < 6 then 'Other Shop' Else T.Shop
         End) as [Shop Code]
From    MyTable T
Group By T.[ID Code],
         T.[ID Name];

Aggregate functions (or expressions with aggregates) don't belong in the GROUP BY . These are calculated in the SELECT , not used to define groups.

Answer 2

You can use the HAVING and UNION ALL statement, like this:

Select  Count(*) as [Activity],
    T.[ID Code],
    T.[ID Name],
    'Other Shop' [Shop Code]
 From MyTable T
Group By T.[ID Code],
      T.[ID Name]
having Count(*) < 6
 union all
Select  Count(*) as [Activity],
    T.[ID Code],
    T.[ID Name],
    T.Shop [Shop Code]
 From MyTable T
Group By T.[ID Code],
      T.[ID Name]
having Count(*) >= 6

Answer 3

select 
count(*) as activity,
code,
name,
Case when Count(*) < 6 then 'Other Shop' Else shopcode End as shopcode
from mytable group by code, name ,shopcode

Answer 4

The example below is a test in SQL Server.

It uses a window function for count, to change the Shop code.
And then groups it all, including that modified shopcode.

declare @ShopTable table ([ID Code] varchar(30), [ID Name] varchar(30), Shop varchar(30));

insert into @ShopTable ([ID Code], [ID Name], Shop) values 
('S1','Shop 1','AA'),
('S1','Shop 1','BB'),
('S1','Shop 1','BB'),
('S1','Shop 1','CC'),
('S1','Shop 1','CC'),
('S1','Shop 1','CC'),
('S2','Shop 2','XX'),
('S2','Shop 2','YY');

select 
count(*) as [Activity], 
[ID Code], 
[ID Name], 
[Shop Code]
from (
  select
   [ID Code],
   [ID Name],
   case when count(*) over (partition by [ID Code], [ID Name]) < 6 then 'Other Shop' else Shop end as [Shop Code]
  from @ShopTable
) Q
group by [ID Code], [ID Name], [Shop Code];