Deborah Melkin has a confession and a defense:
I feel like this is where I should say something like, “Hi, my name is Deborah and I’ve used nolock in production.” I would also have to confess to doing things like using correlated sub queries, not using a foreign key, implemented complicated triggers, etc. I often talk about how the first real SQL script I wrote had cursors running over temp tables in SQL Server 6.5, which I’m fairly certain was one of the first thing I read you were NOT supposed to do. And oh, hello there, denomalized table and dynamic SQL! I’m sure I’ve done more things than this too. These are just the ones I can remember doing, or at least I’m willing to admit in public.
With some of these, the answer is “that’s the best alternative I had at the time.” With correlated sub-queries, I wouldn’t even consider that a bad thing. Granted, I personally prefer a combination of common table expressions and the APPLY
operator but that’s usually not for performance reasons.