Insert statement that checks for duplicate before insert

Question

I need to make a insert but only if similar record don\'t exists
for example:

INSERT INTO requests (\'user_id\',\'subject\',\'text\',\'time\') V

Answer 1

Replace your query from

INSERT INTO requests ('user_id','subject','text','time') VALUES (56,'test','test 1234',6516516)

To,

REPLACE INTO requests ('user_id','subject','text','time') VALUES (56,'test','test 1234',6516516)

This will add a small delay to the execution, but it is more efficient than any other method