MySQL - ignore insert error: duplicate entry

You can use INSERT... IGNORE syntax if you want to take no action when there's a duplicate record.

You can use REPLACE INTO syntax if you want to overwrite an old record with a new one with the same key.

Or, you can use INSERT... ON DUPLICATE KEY UPDATE syntax if you want to perform an update to the record instead when you encounter a duplicate.

Edit: Thought I'd add some examples.

Examples

Say you have a table named tbl with two columns, id and value. There is one entry, id=1 and value=1. If you run the following statements:

REPLACE INTO tbl VALUES(1,50);

You still have one record, with id=1 value=50. Note that the whole record was DELETED first however, and then re-inserted. Then:

INSERT IGNORE INTO tbl VALUES (1,10);

The operation executes successfully, but nothing is inserted. You still have id=1 and value=50. Finally:

INSERT INTO tbl VALUES (1,200) ON DUPLICATE KEY UPDATE value=200;

You now have a single record with id=1 and value=200.