Tables or result sets sometimes contain duplicate records. Sometime it is allowed but sometime it is required to stop duplicate records. Sometime it is required to identify duplicate records and remove them from the table. This chapter will describe how to prevent duplicate records occurring in a table and how to remove already existing duplicate records.
Showing posts with label insert. Show all posts
Showing posts with label insert. Show all posts
Wednesday, September 16, 2009
INSERT ON DUPLICATE KEY UPDATE - MySQL
INSERT ... ON DUPLICATE KEY UPDATE is a very powerful but often forgotten MySQL feature. It was introduced in MySQL 4.1.
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