A field filter performs the same function as a table filter. But the field filter sets a filter only on the field that contains the cursor when you choose the function. It is a good idea to check your filters by occasionally using the table filter function to get an overview of all the filters that have been set in a window.
Here is a description of how to use a field filter to filter the Customer table so that the only customer cards displayed are those on which the salesperson code is PS.
Open the 
Customer Card
window.
Click the Salesperson Code field.
On the menu bar, click View, Field Filter.
In the window that appears, enter the criteria to be met. To begin with, the filter field has the same contents as the field on the card, but just type over the contents.
Enter PS, and then click Apply.
If you browse through the customer cards now, you will see only cards that have PS as the salesperson code. The other customers are still in the database, but you won't see their cards until you remove the filter:
On the menu bar, click View, Show All.
Now you can see all the cards in the Customer table again.
If you want filters on more than one field, you must set a table filter.
There are three buttons (plus Help) in the filter window. Click Apply to apply the filter you have entered in the field and see the result (while leaving the filter window open). Click OK to apply the filter and close the filter window. Click Cancel to close the filter window without saving changes you have made in the filter field since you last clicked Apply or OK.
It is important to enter only meaningful filters. For example, it is possible to specify an interval that does not exist, and the program cannot check this for you. In order to enter meaningful filters, you must know the sorting rules that the program follows.