Duplicate Customers

Hi All,

I am facing below issues.

1) We are using TCA.

2) Client reported that there is a duplicate party/customer.

3) Navigation  AR resp > Customer > Entered "Account Number"

   It feched duplicates customers.

4) I ran the " Duplicate Customer report" but do not  know significance of parameter "Number of Customer".

But ran the report by putting 1000 values...but the output was Null.

Why? Do not know.

5) CAN anyone provide SQL query to identify duplicate customers .

6) How to resolve the above issue.

Thanks,

Regards,

Yogesh