Sql Server 2005 - Insert if not exists

Question

There is lots of information in the internet regarding this common \"problem\".

Solutions like:

IF NOT EXISTS() BEGIN INSERT INTO (...) END
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Answer 1

To answer the updated question repeatable read would still not be sufficient.

It is holdlock / serializable level that you would need.

You are trying to prevent phantoms (where on the first read no rows met the criteria so the NOT EXISTS returns true but subsequently a concurrent transaction inserts a row meeting it)