If you have an aggregation function (sum, avg, count) in your select clause or if you have a group by clause, all of your columns must be aggregated or grouped.<BR><BR>In the version of SQL that I ...

SQL window functions provide extremely powerful and useful features that let you work with observations more easily. Different types explained here.

Learn how to master the SELECT statement to form truly useful data queries. This article explains functions, clauses, and keywords that will make your life a lot easier.

I realized how much easier my life would be if SQL had a mode() aggregate function. (I'm using it in the mathematical sense). I'm guessing that either I use SQL in a wierd way or there is a good ...