November 23, 2009 at 11:58 pm
Well I am dealing with very small number of records, something like 30+ so I am not much concerned about performance. Especially having the fact that the job runs once a week.
As for using '%', '_' or equality operand, since my databases names look like HotDog{two letter country code}XYZ, I found using '_' works the best for me. If the databases were named something like this HotDog{two letter country code}, I could probably use left(db_name, 6) and equality operand.
I am open to other ideas though. 🙂
November 24, 2009 at 12:09 am
I'm not one to argue with results! Theory is often best practiced in the classroom:-)
--SJT--
November 24, 2009 at 1:20 am
When the query is executed - the JOIN clause gets evaluated first and the WHERE Clause operates subsequently on the rows returned by the JOIN clause. It seems therefore that in the earlier version of the query - the JOIN clause itself was not sufficient in that it was not returning the right result set rendering the WHERE clause ineffective. It sounds that promoting the condition to the JOIN clause helped in retrieving the correct rows upfront.
Again the filtering on the NULL actually makes the other conditions useless as pointed out by another poster. Be that as it may, would the OP kindly confirm this is what was happening so I can verify my understanding?
Saurabh Dwivedy
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http://www.sqlservercentral.com/articles/Best+Practices/61537
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