Question

When no AUTO_INCREMENT value has been generated during the current connection, LAST_INSERT_ID() returns ____________

(a) -1

(b) 0

(c) 1

(d) 2

The question was asked in an interview for job.

This is a very interesting question from Working with Sequences topic in chapter Data Types of MySQL

Answer 1

Right choice is (b) 0

Easy explanation: The ‘LAST_INSERT_ID()’ function returns zero when no ‘AUTO_INCREMENT’ value has been generated during the current connection with the server. It is tied to the current connection.