nested query vs jOINs

Question

whos could be much efficient if I use nestted subquery, JOINs Or maybe temp tables .. another question : in subqueries if i use IN Cl

Answer 1

Joins are far quicker than the other suggestions you made.

Joins will perform the ON condition for every record whereas doing selects with a WHERE will pull in ALL records first, then perform the filter, thus being much slower.

Joins all the way !!