Question

I would like to have an insert and update if exists operation on my db.

My table has ‘A’ defined as PRIMARY.

A int
B VARCHAR 20
TEST int

why does this query returns ‘2 row(s) inserted’ instead of 1?

insert into test1 (A, B, TEST) 
values(2, "A", 19) 
on duplicate key update 
A=values(A), B=values(B), TEST=values(TEST)

Answer 1

With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row is inserted as a new row and 2 if an existing row is updated.

http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html

This believed to distinguish between a brand new row vs update on existing row