Window functions to count distinct records

Question

The query below is based on a complicated view and the view works as I want it to (I\'m not going to include the view because I don\'t think it will help with the question a

Answer 1

I came across this question in search for a solution to my problem of counting distinct values. In searching for an answer I came across this post. See last comment. I've tested it and used the SQL. It works really well for me and I figured that I would provide another solution here.

In summary, using DENSE_RANK(), with PARTITION BY the grouped columns, and ORDER BY both ASC and DESC on the columns to count:

DENSE_RANK() OVER (PARTITION BY drugClass ORDER BY drugName ASC) +
DENSE_RANK() OVER (PARTITION BY drugClass ORDER BY drugName DESC) - 1 AS drugCountsInFamilies

I use this as a template for myself.

DENSE_RANK() OVER (PARTITION BY PartitionByFields ORDER BY OrderByFields ASC ) +
DENSE_RANK() OVER (PARTITION BY PartitionByFields ORDER BY OrderByFields DESC) - 1 AS DistinctCount

I hope this helps!