Posted by For some giggles this Halloween, over on Twitter I tweeted some worst practices each hour during Halloween in the guise of carved pumpkins. Here’s the complete set spanning the 24 hours – hopefully you do not recognise any of these in your data centre!
Learning is not a spectator sport 
I would like to add:
1- no need to use to_date
2- use V function without conversion
3- filter in loop, not in select
I am suffering because of those 🙂