Question

Having some trouble with some SQL.

Take the following result for instance:

LOC_CODE     CHANNEL            
------------ -------------------- 
3ATEST-01    CHAN2            
3ATEST-01    CHAN3            
3ATEST-02    CHAN4            

What I need to do is get a count of the above query, grouped by channel, but i want that count to be divided by the count that the “LOC_CODE” appears.

Example of the result I am after is:

 CHANNEL          COUNT
 ---------------- ----------
 CHAN2            0.5
 CHAN3            0.5
 CHAN4            1

Above explaination is that the CHAN2 appears next to “3ATEST-01”, but that LOC_CODE of “3ATEST-01” appears twice, so the count should be divided by 2.

I know I can do this by basically duplicating the query with a distinct count, but the underlying query is quite complex and don’t really want to harm performance.

Please let me know if you would like more information!

Answer 1

Try:

select channel, 
       count(*) over (partition by channel, loc_code)
        / count(*) over (partition by loc_code) as count_ratio
from my_table