RE: Need help with merge – SQLServerCentral

SSC Guru

Points: 186127

January 30, 2014 at 2:16 am

Use a traditional upsert.

What you're trying to do in your original MERGE is to update rows which don't exist.

Perform your inserts first from a deduped source set - that is, deduped on whatever you are using to determine uniqueness. The remaining rows of your source set are all updates. You could use ROW_NUMBER() to distinguish between the two. EXISTS is the first option I'd experiment with for determining which of the deduped rows to insert into the target.

Edit: clarity

^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

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