omid.shokri (7/7/2013)
Thanks for reply.This query is the part of a procedure.
I think no different these two query, but output of query 1 is without any row. In other word, "Inner Join dbo.CustomerCreditD" is cause of the result.
There's a significant difference between an INNER join and an OUTER join. With an inner join, table sequence doesn't matter that much, but with an OUTER join, it's a big deal.
Maybe you should test on really small data sets - maybe 5-10 records in each table, maximum. Then once you can examine the results and make sense of how you got there, you'll understand it better. One way of doing something like that is to insert a small handful of records into a temporary table, and then query the temporary table...