Question

Performance wise, what is better?
If I have 3 or 4 join statements in my query or use embedded select statements to pull the same information from my database as part of one query?

Answer 1

I would say joins are better because:

1. They are easier to read.
2. You have more control over whether you want to do an inner, left/right outer join or full outer join
3. join statements cannot be so easily abused to create query abominations
4. with joins it is easier for the query optimizer to create a fast query (if the inner select is simple, it might work out the same, but with more complicated stuff joins will work better).
5. embedded select‘s can only simulate left/right outer join.

Sometimes you cannot do stuff using joins, in that case (and only then) you’ll have to fall back on an inner select.