LINQ subquery “NOT IN” problem

Question

I do not understand why this query fails.

var qTags = from tagsU in _context.ADN_ProductTagsView
where !(from o in _context.ADN_ProductTagsView
        where         


        

Answer 1

Try .Any

var qTags = from tagus in _context.ADN_ProductTagsView
            where !tagAux.Any(t=> t== tagus.ProductTagID)
            select tagus ;

btw, did not run the query, so please check the syntax.

Answer 2

It seems that the implementation of the QueryProvider you're using isn't complete. I'm not familiar with the QueryProvider you're using, but maybe you can try something like this:

var qTags = from tagsU in _context.ADN_ProductTagsView
where !(from o in _context.ADN_ProductTagsView
        where o.ProductID == productId
         select o.ProductTagID).Any(tagId => tagId == tagsU.ProductTagID)
select tagsU;

Hope that helps