Question

I would like to create a LINQ query which results in the following SQL statement. Let’s say I have a simple table with just two character fields – field1 and field2. My SQL statement would be:

    SELECT field1, field2, field1+field2 AS ConcatField
    FROM TableX
    WHERE field1+field2 = 'abcdef'

How can this be done in LINQ?

Answer 1

You can use a let clause for defining your concatfield and then select an anonymous type with the 3 fields you want to return.

from f in TableX
let concatfield = f.Field1 + f.Field2
where concatfield = 'abcdef'
select new
{
  f.Field1,
  f.Field2,
  concatfield
}

Regarding to your example of the more complex where clause,you would need to build an array of the values you want to compare to and then do something like this:

  List<string> values = .....

  from f in TableX
  let concatfield = f.Field1 + f.Field2
  where values.Contains(concatfield)
  select new
  {
     f.Field1,
     f.Field2,
     concatfield
  }