Question

What does LAST_INSERT_ID() return when no AUTO_INCREMENT value has been generated during the current connection?

(a) -1

(b) 0

(c) 1

(d) 2

I have been asked this question during an online interview.

Enquiry is from Internal Security: Preventing Unauthorized Filesystem Access topic in chapter Access Control and Security of MySQL

Answer 1

Right answer is (b) 0

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.