[Logician]

general rule is this:

Whenever you see PHP command "mysql_query" add 1 query to your server load. For vb scripts the keyword is "$DB_site->query" or "$DB_site->query_first"..

But sometimes less query doesnt mean the best performance. If your query is too advanced or badly formed, it can sometimes eat more server source than 2 independent queries. But well these are expert tips, for your needs you can count on the idea that less query = less server load.

Too much server load is not always bad for all sites. Say you are on dedicated, have a powerful computer or less site visitors, then you can go crazy with your queries. But for many people who are on shared hosting when you increase your queries, it means you are taking the shared server load from your neighbours which you hosting company wouldnt like if you consume too much power very frequently..