Demand Planner Client - SQL Statement

Hi, 

Does anyone have any experience of using ‘or’ statements in demand flow SQL statements?

We are trying to create a demand flow for demand planner client using an “or” in the sql statement to exclude some customers.

Our statement is:

Select contract, part_no, issue_date, issue_qty from IFSAPP.external_invent_part_issue_pub  where CUSTOMER_NO <> 'CUST1' or CUSTOMER_NO <> 'CUST2'

The flow doesn't error out and is created in the client, but the quantities in the created flow are still the total demand, so no exclusions are being done.

Thanks