SQL Query to return 24 hour, hourly count even when no values exist?

Question

I\'ve written a query that groups the number of rows per hour, based on a given date range.

SELECT CONVERT(VARCHAR(8),TransactionTime,101) + \' \' + CONVERT(         


        

Answer 1

I've run into a version of this problem before. The suggestion that worked the best was to setup a table (temporary, or not) with the hours of the day, then do an outer join to that table and group by datepart('h', timeOfRecord).

I don't remember why, but probably due to lack of flexibility because of the need for the other table, I ended up using a method where I group by whatever datepart I want and order by the datetime, then loop through and fill any spaces that are skipped with a 0. This approach worked well for me because I'm not reliant on the database to do all my work for me, and it's also MUCH easier to write an automated test for it.