Question

I have a table with the following columns:

  A   B   C --------- 1   10  X 1   11  X 2   15  X 3   20  Y 4   15  Y 4   20  Y  

I want to group the data based on the B and C columns and count the distinct values of the A column. But if there are two ore more rows where the value on the A column is the same I want to get the maximum value from the B column.

If I do a simple group by the result would be:

  B   C    Count -------------- 10  X    1 11  X    1 15  X    1 20  Y    2 15  Y    1  

What I want is this result:

  B   C    Count -------------- 11  X    1 15  X    1 20  Y    2  

Is there any query that can return this result. Server is SQL Server 2005.

Answer 1

I like to work in steps: first get rid of duplicate A records, then group. Not the most efficient, but it works on your example.

with t1 as (     select A, max(B) as B, C          from YourTable         group by A, C ) select count(A) as CountA, B, C     from t1     group by B, C