Is order by clause allowed in a subquery

Question

Is there any reason why or why not you should do an \'order by\' in a subquery?

Answer 1

Depending on the size of the sub-query, it will impact performance to a varrying degree.

Order shouldn't matter on a sub-query though. You should be able to move the Order By portion to the Outer Query (which should be the one returning the final results).