I invite you all to visit my website that has a book about the weaknesses SQL has on Database Processing. All the examples had been tested in DB2, but the situation is practically the same and in some cases still worse in other SQL DBMS. This publication explains aspects related to:
• Equivalent queries may produce different results.
• Aggregation operators like SUM, AVG, etc. doesn’t generate the correct calculation in certain cases.
• Query tables that have nulls may lead us to misinterpret results in a variety of cases.
It’s essential for us to be conscious about the weaknesses this language has in order to avoid them. I hope it’s useful:
The publication: http://stores.lulu.com/dbtips
A couple of weaknesses explained in my blog: http://dbtips.wordpress.com/
and its video clip in youtube.com: http://www.youtube.com/watch?v=FWrH5K6V6E0
Contact me: email@example.com
Thanks for reading,
O. F. Domejean