INSERT … ON DUPLICATE KEY UPDATE with WHERE?

Question

I\'m doing a INSERT ... ON DUPLICATE KEY UPDATE but I need the update part to be conditional, only doing the update if some extra condition has changed.

Answer 1

On duplicate key do not allow us to use where clause, so there are two alternative to achieve the same.

1. If you know most of the time you will get the duplicate key then

   a. Update the table first using update query and where clause b. If update fails then insert the record into table using insert query

2. If you know most of the time you are going to insert into table then

   a. Insert the record into table using insert ignore query - what it does is actually ignore the insert if duplicate key found b. If insert ignore fails then update the record using update query

For reference of insert ignore click here