Question

I have a table that has the following data (shortened for this example):

    C1    C2    C3    C4
=========================
1   0     1     1     0
2   1     1     0     1
3   1     0     1     1
4   1     1     1     1
5   0     0     1     1
6   0     0     0     1

I want to create a create a query that gives me the following result:

    C3    C4
=============
C1   2     3 
C2   2     2

That is, the combination of those four columns when:

C1 = 1 & C3 = 1
C1 = 1 & C4 = 1
C2 = 1 & C3 = 1
C2 = 1 & C4 = 1

I’ve been able to get make some progress, but not ultimately what I want. I’ve managed to get this far: http://sqlfiddle.com/#!3/7d3d4/2/0

but I can’t figure out how to get my query to format like my desired output above. I was going to try to use a PIVOT table, but quickly abandoned that idea because it seemed to get extremely convoluted once I needed to add a 2nd PIVOT statement (and I’d end up having to add more as my example above is a really basic example of the number of columns I need to perform this on).

What am I missing?

Thank you.

Answer 1

try this:

SELECT 'C1',SUM(CASE WHEN C1=1 AND C3=1 THEN 1 END)AS C3,
            SUM(CASE WHEN C1=1 AND C4=1 THEN 1 END)AS C4
FROM T1
UNION ALL
SELECT 'C2',SUM(CASE WHEN C2=1 AND C3=1 THEN 1 END)AS C3,
            SUM(CASE WHEN C2=1 AND C4=1 THEN 1 END)AS C4
FROM T1

SQL Fiddle Demo