database server

I intend to set a database server running in the not so far future and id like to know a few things here. Firstly what kind of speed can i achieve with MySQL? I hear of tables with millions of rows but i have no clue how fast data can be retrieved yet. I also hear ppl complaining about subqueries not available on mySQL, what exactly are they anyway? And finally, could someone running a database server give me some basic info concerning bandwidth vs # of hits.
Answers would be very appreciated.
Thanks.

Here's a link to the benchmarks listed on MySQL's site. It should provide you with all of the information you need about benchmarks and speed.
www.mysql.com/benchmark.html

And here is the scoop on subqueries. A subquery is basically a way to combine to queries into one. Here is a link that should be able to explain it better.
http://www.geocities.com/SiliconValley/Vista/2207/sql3.html#Aliases+&+In%2FSubqueries

[This message has been edited by moderator (edited 09-28-99).]