MySQL insert where not exists / if not exists

Question

I have tried the following query:

INSERT INTO `surfed_site` (user, site)
VALUES (\'123\', \'456\')
WHERE NOT EXISTS (SELECT site FROM `surfed_site` WHERE site=456         


        

Answer 1

INSERT statements support two1 syntaxes: one that uses VALUES, and one that uses a query. You can't combine them, and only the query syntax supports WHERE clauses. So:

INSERT INTO `surfed_site` (user, site)
SELECT '123', '456' FROM (SELECT 1) t
WHERE NOT EXISTS (SELECT site FROM `surfed_site` WHERE site=456)

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1. Actually three syntaxes; you can also use SET. If you're only inserting one record, this one is functionally equivalent to VALUES, but arguably more readable.