Sorting on the server or on the client?

Question

I had a discussion with a colleague at work, it was about SQL queries and sorting. He has the opinion that you should let the server do any sorting before returning the rows

Answer 1

Generally I agree with the views expressed above that server-side sorting is usually the way to go. However, there are sometimes reasons to do client-side sorting:

• The sort criteria are user-selectable or numerous. In this case, it may not be a good idea to go adding a shedload of indices to the table - especially if insert performance is a concern. If some sort criteria are rarely used, an index isn't necessarily worth it since inserts will outnumber selects.
• The sort criteria can't be expressed in pure SQL [uncommon], or can't be indexed. It's not necessarily any quicker client-side, but it takes load of the server.

The important thing to remember is that while balancing the load between powerful clients and the server may be a good idea in theory, only the server can maintain an index which is updated on every insert. Whatever the client does, it's starting with a non-indexed unsorted set of data.