Question

Hope I can make myself clear:
I have a categories table with CategoryID’s and a boolean field Available.

   Dim catquery = _
         From cat In SQLEngine.DigiwaiterSQLDataSet.Categories
         Where cat.Field(Of Boolean)("Available") = True
         Select cat

I also have a products table with an available boolean field and a CategoryID which indicates what category the product belongs to.

Dim prodquery = _
         From prod In SQLEngine.DigiwaiterSQLDataSet.Products
         Where prod.Field(Of Boolean)("Available") = True
         Select prod

How can I use LINQ to also check the Categories table / Catquery to see if the Category for the product is Available?

Thnx,

Mike

Answer 1

You can use a join:

Dim prodquery = _
         From prod In SQLEngine.DigiwaiterSQLDataSet.Products
         Join cat in SQLEngine.DigiwaiterSQLDataSet.Categories
             On prod.Field(Of Int32)("CategoryId") Equals cat.Field(Of Int32)("CategoryId")
         Where prod.Field(Of Boolean)("Available")
         AndAlso cat.Field(Of Boolean)("Available")
         Select prod

(I removed the = True part, which is useless)