check new customer is exist in table

[lgxdo]

hi all,

I have one question like that:

I have one customer table: customerID, name,address,phone,zip.......
I must check the customer in this table or not before insert it. The
records of the table is 1000K, I will check the zip, name and address,
if all are same, it is exist. but sometime address is not matching
100%,
like: "1111 N robinson ok city" and "1111 N Robinson oklahoma
city"
or "111 N robinson street" and "111 N robinson ST"
anyone can give me some advice?
Thanks
Alber