May 20, 2014 at 2:20 pm
I have a lookup Im using to replace a left join merge join in a package. I set my Lookup to use full cache, ignore failure for the drop down under "Specify how to handle rows with no matching entities" as well as in the error tab I have lookup match output to ignore failure as well as every column has Ignore Failure. But all of the records arent being passed through...why is this?
May 20, 2014 at 2:38 pm
I think I known why this is happening. Ther merge join's left join will join the left input records with every record it matches on which could be more than one record. The lookup passes the record through the lookup after it finds its first match.
If this is incorrect someone please chime in?
May 20, 2014 at 2:44 pm
With a lookup component set to ignore failure, the number of rows is exact the same as the number of rows that go on.
If a lookup finds multiple matches, it only takes the first one.
With the merge join it is indeed possible that one row from the left input is matched to multiple rows from the right input.
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