Check your relationships and the data in the match field you've selected in Inventory for this relationship. The blank column suggests that there is no record in Inventory with a matching Item ID. Check the data type of both fields, check the data in the fields and check what link you've established in Manage | Databae | Relationships to link the two tables.
I did that. For example the Item ID CHIP35 exists in both tables. Both fields say the type is "text". Is there any other definitions of data I should look at?
Thanks for your help.
What do you see on the relationships tab linking the two tables?
Do you see SalesData::Item ID = Inventory::Item ID ?
Also, make sure there are no nonprinting characters such as a space making the value in one record different from the the other even though they look the same.