Is using COUNT(*) or SELECT * a good idea?

Question

I\'ve heard several times that you shouldn\'t perform COUNT(*) or SELECT * for performance reasons, but wasn\'t able to dig up some further informa

Answer 1

COUNT(*) is different from COUNT(column1) !
COUNT(*) returns the number of records, and does NOT use more resources, while COUNT(column1) counts the number of records where column1 is non null.

For SELECT, it is different. SELECT * will of course request more data.