Hey there friend,
It's 3AM...but let me see if I can help you at all.
I think you are on the right track when you say a new database. It sounds like you need 2 tables...
Table #1 Customer Table containing:
customer phone number
Table #2 Order Table containing:
id_of_customer //referring to the customer on the customer table
order //you need to figure out the data here
You could even have a third table with info about each item in the store, and then an order could be a comma seperated list of items purchased...that would give the most complete data....but would require someone to sit down and add each type of thing in the store to the inventory
When you have the 2 tables and you want to get all orders for a certain customer you will be searching your mysql table WHERE id_of_customer= whatever their id is.
Hope this helps.