Insert Ignore and Replace in MySql

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Use INSERT IGNORE rather than INSERT. If a record doesn't duplicate an existing record, MySQL inserts it as usual. If the record is a duplicate, the IGNORE keyword tells MySQL to discard it silently without generating an error.

Following example does not error out and same time it will not insert duplicate records.

mysql> INSERT IGNORE INTO person_tbl (last_name, first_name) -> VALUES( 'Jay', 'Thomas'); Query OK, 1 row affected (0.00 sec) mysql> INSERT IGNORE INTO person_tbl (last_name, first_name) -> VALUES( 'Jay', 'Thomas'); Query OK, 0 rows affected (0.00 sec)

Use REPLACE rather than INSERT. If the record is new, it's inserted just as with INSERT. If it's a duplicate, the new record replaces the old one:

mysql> REPLACE INTO person_tbl (last_name, first_name) -> VALUES( 'Ajay', 'Kumar'); Query OK, 1 row affected (0.00 sec) mysql> REPLACE INTO person_tbl (last_name, first_name) -> VALUES( 'Ajay', 'Kumar'); Query OK, 2 rows affected (0.00 sec)

INSERT IGNORE and REPLACE should be chosen according to the duplicate-handling behavior you want to effect. INSERT IGNORE keeps the first of a set of duplicated records and discards the rest. REPLACE keeps the last of a set of duplicates and erase out any earlier ones.