how to create admission number for student [PHP +SQL]

Question

It has suffered me to create an ad_number to a student..
I have three class A,B and C , i want class "A" student id to start with 170101 then increament by 1... class "B" student id to start with 170201 then increament by 1..class "C" student id to start with 170301 then increament by 1..

I haved created sql table for each class

Answer 1

//Use php Auto Increment on Id columns ,that will be better