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 ...

In addition to using subselects to examine data in related tables, it’s also possible to use an aggregate function in a WHERE clause subselect to make a determination about the primary result set.

SQL window functions are calculation functions similar to aggregate functions but, unlike normal aggregate functions like “group by,” have access to individual rows and can even add some of ...

The aggregate is not used to set the value of the field only in determining what to set the value of the field to. E.G. UPDATE A SET A.SomeField = CASE ...