Avoid error on INSERT with UNIQUE CONSTRAINT

I've altered my table by adding a UNIQUE CONSTRAINT to avoid inserting duplicate records, however now I have an issue with INSERT, when it encounters a duplicate in the table and throws an error, which breaks my code.

ALTER TABLE `t1` ADD UNIQUE `unique_index`(`user`, `email`);

Is there a way to modify the query to simply ignore the insert when a duplicate index is found and go to another insert, since I'm doing it via a loop for multiple values? Or do I need to add a SELECT query first to check if the duplicate exists, which seems pretty inefficient?

My current query looks like:

INSERT INTO t1 (`user`, `email`) 
VALUES ('".$row['user']."', '".$email."')

You can use INSERT IGNORE instead of INSERT.

INSERT IGNORE INTO t1 (`user`, `email`) 
VALUES ('".$row['user']."', '".$email."')

However, using INSERT IGNORE can sometimes be risky, as it ignores all other errors, not just the duplicate key error.

A safer alternative is to use INSERT ... ON DUPLICATE KEY UPDATE. Although it's primarily intended to perform an update to the row where a key conflict occurs, you can make it do nothing.

INSERT INTO t1 (`user`, `email`) 
VALUES ('".$row['user']."', '".$email."')
ON DUPLICATE KEY UPDATE `user`=`user`;

This statement inserts new rows with the specified values, or if a row causes a duplicate key error, it does nothing and moves on to the next row. It's a safer option because it ignores only duplicate key errors. Other types of errors still interrupt the statement and return an error message.