Question

It’s a rather simple query but I can’t seem to get it done in EF.

The C# equivalent of:

SELECT A1, A2 from TABLEA WHERE A3 NOT IN ( SELECT B1 FROM TABLEB WHERE ... ) 
   AND A4 IN ( SELECT C2 FROM TABLEC WHERE .... )

I would prefer to have the query run on the database as tableB has > 5000000 rows so performance is a big factor.

Answer 1

Like this

var b1s = from b in TableB
          where ...
          select b.B1;

var c2s = from c in TableC
          where ...
          select c.C2;

var a1sAndA2s = from a in TableA
                where !b1s.Contains(a.A3)
                   && c2s.Contains(a.A4)
                select new {
                    a.A1,
                    a.A2
                };

To see the SQL statement being generated you can either use the SQL statement tracer (don’t quote me on the name but it’s built into VS2010) or grab the statement as a String via

String sqlStatement = (a1sAndA2s as ObjectQuery).ToTraceString();