MYsql INSERT ON DUPLICATE KEY UPDATE with IF

this one helps. i think you have to index your table in mysql such that if any new data enters that have any similar date and entry the mysql will automatically pop out a duplicate entry error

like below fixes the issue I tried to do an INSERT without the "ON DUPLICATE KEY UPDATE" and MySQL responded with a helpful error that actually pointed to the REAL problem. It told me that the value I was inserting for the foreign key (Location) was a 'violation'. This was the case because there was no record in the Location table with key 0. I updated my sample insert to use a valid Location foreign key and that worked. The update succeeded.
So in short, make sure you are inserting valid values! ;)

I wish did fix the issue. Semantically you're trying to express "Insert a new view for this post, but if it already have a view, add one".
This can be done with:

INSERT INTO `views` (post_id, view_count, view_ip)
VALUES (?, 1, ?)
ON DUPLICATE KEY UPDATE view_count = view_count + 1;

view_ip = ?

view_ip = "'.$ip.'"

This might help you INSERT IGNORE and INSERT ... ON DUPLICATE KEY UPDATE are mutually exclusive. They both handle the situation when the row to be inserted conflicts with an already existing row on an UNIQUE INDEX.
IGNORE converts the errors into warnings and this basically lets the query succeed and ignore the new values.

INSERT INTO Inventory VALUES('PA', 'Area 1', NOW(), NULL)
ON DUPLICATE KEY UPDATE
    `In` = IF(ISNULL(`In`), VALUES(`In`), `In`),
    `Out` = NULL

hop of those help? I'm trying to use the funcion INSERT INTO ... ON DUPLICATE KEY to insert some data in a mySQL table. And if there's already a user registered with the same email, i want to update the values. , The column email should be UNIQUE.

ALTER TABLE `theElisa_signUpADD` UNIQUE (email);