Selecting columns in a query
I've always known this, but I thought I would share it.
I just did a quick performance test on two queries using the Sql Server Profiler. The difference between the two queries was
Query 1: select * from table where...........
Query 2: select col1, col2, ..... from table where........
There is a small, but noticable performance difference in the two queries. Query 1 was significantly slower on the first call versus Query 2, somewhat slower on the second call, and performed the same on subsequent calls. While this was particular to my application, I think it is something I would suggest to all developers to specifically specify the columns in a query.