UPDATE if exists else INSERT in SQL

Question

I\'m trying to implement a SQL query to \"UPDATE if exists else INSERT\"

My table(Allowance) is as below:

EmployeeID int(8) PK
Year year         


        

Answer 1

No need to write custom SQL for this. MySQL already has INSERT ... ON DUPLICATE KEY UPDATE which does exactly same thing.

If you specify ON DUPLICATE KEY UPDATE, and a row is inserted that would cause a duplicate value in a UNIQUE index or PRIMARY KEY, an UPDATE of the old row is performed.

Please read URL for more details.