Complex Queries Versus Many Queries

One important query design question is whether it’s preferable to break up a complex query into several simpler queries. The traditional approach to database design emphasizes doing as much work as possible with as few queries as possible. This approach was historically better because of the cost of network communication and the overhead of the query parsing and optimization stages.

However, this advice doesn’t apply as much to MySQL, because it was designed to handle connecting and disconnecting very efficiently and to respond to small and simple queries very quickly. Modern networks are also significantly faster than they used to be, reducing network latency. Depending on the server version, MySQL can run well over 100,000 simple queries per second on commodity server hardware and over 2,000 queries per second from a single correspondent on a gigabit network, so running multiple queries isn’t necessarily such a bad thing.