Question

Basically, I have three tables, lets call them TableA, TableB and TableC.

Table A & B have two columns of interest, ID & Value. Table C has three columns, ID, A_ID and B_ID.

I’m looking to construct a LinqToSQL query that:

• Returns the Value from Tables A and B where Table C has a record containing both A & B’s ID’s

Example:

The returned records should be of a specific type:

public class RecordClass
{
    string A_Value;
    string B_Value;
    public RecordClass()
    {
        A_Value = "";
        B_Value == "":
    }
}

Can anybody help please?

Answer 1

Sounds like you just want an inner join:

 var query = from a in tableA
             from b in tableB
             join c in tableC on new { A_ID = a.ID, B_ID = b.ID } 
                          equals new { c.A_ID, c.B_ID }
             select new RecordClass { A_Value = a.Value, B_Value = b.Value };

EDIT: Alternatively, if you’ve got your LINQ to SQL model wired up correctly, it could be much simpler:

var query = tableC.Select(c => new RecordClass { A_Value = c.A.Value,
                                                 B_Value = c.B.Value });