c# - Linq many to many selection -

i have 2 tables many many relationship, in post-detail page want show related posts, related posts post have @ least category of current post. how can select related posts of current post? tried code , it's not want:

    [childactiononly]     public partialviewresult getrelatedpost(int id)     {         var relatedposts =             _db.posts.select(x => new { x.id, x.title, x.slug, x.image, x.isactive,x.posttype,x.postcategories })                 .where(x => x.isactive && x.id != id && x.postcategories.intersect(_db.postcategories).any())                 .orderbydescending(x => x.id).take(20)                 .tolist();     } 

update: solve problem code:

            var posts =             _db.posts.select(x => new { x.id, x.title, x.slug, x.image, x.isactive,x.posttype,x.postcategories })                 .where(x => x.isactive && x.id != id && x.postcategories.intersect(_db.postcategories.where(y=>y.posts.any(p => p.id==id))).any())                 .orderbydescending(x => x.id).take(20)                 .tolist(); 

is best way?

i think need select primary key of postcatagories during intersect:

[childactiononly] public partialviewresult getrelatedpost(int id) {     var relatedposts =         _db.posts.select(x => new { x.id, x.title, x.slug, x.image, x.isactive,x.posttype,x.postcategories })             .where(x => x.isactive && x.id != id && x.postcategories.select(y => y.id).intersect(_db.postcategories.select(y => y.id)).any())             .orderbydescending(x => x.id).take(20)             .tolist(); }).any())             .orderbydescending(x => x.id).take(20)             .tolist(); }