Performance problems are often caused by poorly formed SQL statements.
“Proper planning and preparation prevents piss poor performance.” – British military adage.
Poorly designed database queries are the leading cause of performance problems.
For performance and simplicity.
Don’t attempt it unless it’s really going to be necessary.
This is a simple database optimization many people overlook.
Use relationships to reduce queries.
Don’t try to optimize your application by guessing which part is slow.
There’s a time and a place for this and it’s not at the beginning.