I'm not good enough with SQL to solve a problem I'm having with a
query. I'm hoping someone can help point me in the right direction. It
doesn't seem like it should be that hard, but it's beyond me. I'll
simplify the question to it's bare essentials.

Take a simple table with 4 columns (Timestamp, VersionNumber, Client,
Speed) representing clients downloading new versions of our software
and what download rates they're getting. I'd like a query that returns
the rows representing the first time each client downloaded each
version. If a client does not download a particular version there
would be no rows for those. A client may download a version several
times but I want only the first of those downloads (smallest
timestamp). There will be many versions of software.

Can anyone help me with this? Thanks!