A really simple VQMod to improve the functionality of the Filter Module within OpenCart.
As standard the Logic behind the Filter module in OpenCart uses an `OR` match for everything. This mod changes that so that Filter Options in different Filter Groups use an `AND` match but within the same Filter Group matches are still `OR`.
This mod was put together for a stationery store so will use that as the use case.
Say we have two filter groups, "Paper Size" and "Binder Depth". The user selects A4 and 11mm for what they want. With the old filter that would return all the products that are A4 and all the products that are 11mm.
With this mod to the filter the results returned would be only those products that are both A4 AND 11mm.
If the user just wanted a thin folder and didn't mind if the folder was 11mm, 15mm or 20mm, then as each of those are in the same filter group the logic would remain OR. So the returned products would be A4 and (11mm, 15mm or 20mm).