August 4, 2011 at 8:56 am
I have a simple issue but don't know which option would be better in performance wise. I appreciate your help. After few data flows, two inputs (lookups) are coming out. One is for new address and the other is old address. Before making use of both addresses, I should make the decision (if both address ids are not null then I should select new address id). Please let me know the proper tool (union all, merge, merger join don't have conditions) with the required condition.
Thanks
August 5, 2011 at 11:39 am
Union/Merge and Merge Join are not the same operator. If you were to map them to SQL Server commands, Union and Merge corresponds to the UNION operator, while Merge Join correspond to the JOIN, FULL JOIN, and LEFT JOIN commands.
If you are talking about having two outputs coming out to compare, which are both part of the same row, then what you want to use is the Merge Join. If you are talking about two data sets coming out, and you want to combine them into one data set, then you can use the Union or Merge operator.
See This WebPage on Books Online for more details on the Union/Merge operators.
It sounds like what you want though, is the Merge Join operator.
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