If you want to insert values into a MySQL table, but only if those values don’t already exist, and you don’t want to use a primary key on the table (and deal with the resulting error suppression ), here’s an elegant one-query method of doing so.
INSERT INTO [table name] SELECT '[value1]', '[value2]' FROM DUAL
WHERE NOT EXISTS(
SELECT [column1] FROM [same table name]
WHERE [column1]='[value1]'
AND [column2]='[value2]' LIMIT 1)
OK, technically it’s not a single query.
But it is only one round trip to the MySQL server.
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