About A Select Command To Execute In My Mysql Database Options

[Carcinosi]

Hello,

I have a MySQL 5.0 Database used for management of my service, with 13 tables.

The two tables most important now are "customers" and "cust_packages".

The table "customers" has one column "cust_email". This column has e-mails of customers of the my service.

The table named "cust_packages" has one column "cpack_canceldate". This column has the date of canceled accounts, for example '2008-04-03'. If the account is not canceled, so this column has '0000-00-00'.

Both tables "customers" and "cust_packages" have "cust_custnr" and "cpack_usernr" respectively with interconnected values.

These columns have an identification number exclusive for each customer.

For example, I have one customer with the number '110002' in the column "cust_custnr" of the table "customers". The same number is in the column "cpack_usernr" of the table "cust_packages".

I want to select all e-mails of customers with canceled accounts.

But there is a problem. The same customer may have two accounts...the same number may appear two or more times in the colum "cpack_usernr" of the table "cust_packages". For example, the customer '110002' in the past cancelled his account, but recently he opened another account. Because this, the same number 110002 appear two times in the column "cpack_usernr" of the table "cust_packages". I need only exclusive customers with canceled accounts.

So, I want to select all e-mails of customers with canceled accounts AND ONLY for customers which appear ONE TIME in the colum "cpack_usernr" of the table "cust_packages".

Thanks.