ON DUPLICATE KEY UPDATE
If inserted row cause a duplicate value in a UNIQUE index or PRIMARY KEY,Then It updated using ON DUPLICATE KEY .
Syntax:
INSERT INTO [table_name] ([field1,field2,…]) VALUES ([val1,val2,..]) ON DUPLICATE KEY UPDATE [val1,val2,..].
Example:
INSERT INTO wordlist (keyword,docid) VALUES (’sample’,3435) ON DUPLICATE KEY UPDATE docid=docid+1
