QGIS filtering a whole field using NOT

Question

I'd like to negate some values from my map using the NOT operator.

However, i need to deselect a whole field which contains over 600 entries so I don't want to select each. Is there a way to do this?

Is it possible to use: NOT SPA_NAME, without specifying the values

Added from answer:

I have a merged layer with many different soil and land use properties. And I'm trying to select areas that meet certain soil and land use conditions.

So far my expression is: SOIL_TEXTURE = 'clay' OR SOIL_TEXTURE = 'loam' AND LAND_USE = 'arable' AND LAND_USE = 'grassland'

So now I'd like to make sure special protected areas (SPA_NAME field) are excluded from the selection, but there are so many values that is wouldn't make sense to individually select each.

On closer look I am seeing that the command SPA_NAME IS NULL didn't work. Areas that are under special protection are still being selected

Could you give some example data/values, because right now I don't really understand your question. — Erik, Mar 04 '19 at 10:28
Possible duplicate of Selecting features with NULL attributes in QGIS? — BERA, Mar 04 '19 at 11:41
Please don't add "thank you" as an answer. Once you have sufficient reputation, you will be able to vote up questions and answers that you found helpful. - From Review — BERA, Mar 04 '19 at 14:21

score 1 · Answer 1 · answered Mar 04 '19 at 12:00

You simply can expand your current expression by AND "SPA_NAME" IS NULL.

SOIL_TEXTURE = 'clay' OR SOIL_TEXTURE = 'loam' AND LAND_USE = 'arable' AND LAND_USE = 'grassland' AND "SPA_NAME" IS NULL

Now it should return all clay and loam areas which are grassy or arable and not within a SPA-area.

QGIS filtering a whole field using NOT

1 Answers1