MySQL custom primary key generator

Question

I have written an invoice module for our reservation system.

So when I create a new invoice, I automatically generate a primary key through MySQL.

However for th

Answer 1

You should use a procedure or a trigger. The particular query that builds your newInvoiceId should be something like this:

SELECT CONCAT(YEAR(now()),count(*)+1) as newInvoiceId
FROM table
WHERE InvoiceId like CONCAT(YEAR(now()),'%');

The only part where i'm not 100% confident is the CONCAT(YEAR(now()),'%')