Question

I have some stored procedures that I need to write against a nasty beast of an database. I need to loop through a table (application) and pull values out of other tables (some are aggerate / averages /etc values) using the application_id from the application table.

So far I have:

declare @id INT
declare app cursor for
    SELECT application_id from application
OPEN app
FETCH NEXT FROM app 
INTO @id
WHILE @@FETCH_STATUS = 0
BEGIN
    SELECT a.NAME_LAST, a.NAME_FIRST, ca.status, (SELECT AVG(score) FROM reviews WHERE application_id = @id), (SELECT count(*) FROM reviews WHERE application_id = @id)  FROM application a, committee_applications ca WHERE a.application_id = ca.application_id AND a.application_id = @id
  FETCH NEXT FROM app INTO @id
END
CLOSE app
DEALLOCATE app

Which is giving me the results I want, but I’m sure there is a cleaner way of doing this, and I can’t seem to make the mental jump today to do this correctly. Could someone point out a better way of doing this as this seems really ugly to me.

Also, it seems like I should be storing these values into a temp table then returning the full results instead of running the SELECT statement one by one.

Any suggestions would be greatly appreciated.

Thanks.

Answer 1

Removing the cursor will probably speed this up a lot. By using a derived table, you can get the counts and averages with one query and join that back to the other tables to get the remaining columns. Like this….

SELECT a.NAME_LAST, 
       a.NAME_FIRST, 
       ca.status, 
       Scores.AverageScore,
       Scores.CountScore
FROM   application a
       Inner Join committee_applications ca 
         On a.application_id = ca.application_id
       Left Join (
         SELECT application_id, 
                AVG(score) As AverageScore, 
                Count(*) As CountScore
         FROM   reviews 
         Group By application_id
         ) As Scores
         On a.application_id = Scores.application_id