Filters are a standard feature of Odoo, available everywhere. They can be an easy way to understand domains
This is a very simple example. We will add a filter to show Quotations that are linked to an Opportunity.
Click on “Filters” and then “Add Custom Filter”. Then select the criteria – in this example that there is an Opportunity for this Quotation:
Click on “Apply” and only one Quotation is displayed:
Now we need to give this filter a name and save it:
Having saved it, the filter is shown in the list.
Enable “developer mode“, navigate to Technical / User-defined Filters and view the filter you created.
OK, yes, I used a filter to search for a filter. Type in “Opportunities” and search in “Filter Name”.
Click on the Filter to see the details:
The domain is: