I am creating a invoice page, for that in the invoice table I have fields like(id, ionvoice_no, invoice_date,client_name,address,service_cost,tax,etc).
While I enter invoice, I don not want to enter invoice, but it should change automatically from 1
previously it has to check whether already invoice number is or not. if it is there each time after submitting it has to increase by one, else it has to set one number by default.
How to do?