how to join 2 tables with lambda expression c#

Question

I have a query turns out that I have to do a filter joining two tables with lambda, is the expression with only one but how do I do it with two?

this is my SQL Query

    declare @Cod_Empresa int
set @Cod_Empresa = 9
select 
Margen.Codigo_Medidor, Margen.Fecha, Margen.Codigo_barra, Margen.Total_Balance
from tb_margen_operativo_cierre Margen, tb_medidor Medi
where Margen.Codigo_medidor = Medi.Codigo_Medidor
and Medi.Codigo_empresa  = @Cod_Empresa

This is my C# Code

 int codigoempresa = 9 
 var margen = cm.tb_margen_operativo_cierre. //I need 2 tables tb_margen_operativo_cierre and tb_medidor
             Where(x => x.Fecha <= fin && x.Fecha >= inicio).
            GroupBy(r => r.Fecha).
            Select(v => new
            {

                Total_Balance = v.Sum(x => x.Total_Balance),

            }).AsEnumerable().Select(x => new tb_margen_operativo_cierre
            {

                Total_Balance = x.Total_Balance,


            }).ToArray();
            for (int i = 0; i < margen.Length; i++)
            {

                valormes = valormes + margen[i].Total_Balance;
                valorgraficodiario[i] = margen[i].Total_Balance;
            }

How do it? thanks

Your LINQ code is not even close to the SQL you posted. I don't see any grouping nor date filtering on the SQL query. Are you sure you posted the correct code? — Camilo Terevinto, Jul 19 '18 at 18:09
Take a look in [Here](https://stackoverflow.com/questions/2767709/join-where-with-linq-and-lambda) see if it helps — Pacheco, Jul 19 '18 at 18:13
What is this? EF? Linq to SQL? Do you have any Navigation Properties, could we see your Entities (at least tb_margen_operativo_cierre) — moi_meme, Jul 19 '18 at 18:14
You Can use Like this My example: https://stackoverflow.com/questions/30977089/asp-net-mvc-5-entity-join/33251844#33251844 — Rajesh Kumar, Jul 19 '18 at 18:15
Perhaps my [SQL to LINQ Recipe](https://stackoverflow.com/questions/49245160/sql-to-linq-with-multiple-join-count-and-left-join/49245786#49245786) would help you? — NetMage, Jul 19 '18 at 21:48

Benjamin RD · Answer 1 · 2018-07-19T21:58:14.057

Well, first one, you have to improve your query, to something like this:

SELECT 
    Margen.Codigo_Medidor, Margen.Fecha, Margen.Codigo_barra, Margen.Total_Balance
FROM 
    tb_margen_operativo_cierre Margen INNER JOIN tb_medidor Medi
ON 
    Margen.Codigo_medidor = Medi.Codigo_Medidor
WHERE 
    Medi.Codigo_empresa  = 9;

Now, if you have relations between your tables, you can do this in LINQ:

Asuming: One Margen could have Many Medi. In LinQ you might use:

from Margen tb_margen_operativo_cierre 
join Medi in tb_medidor on Margen.Codigo_medidor equals Medi.Codigo_Medidor
where Medi.Codigo_empresa == 9;

And the result should be the same of your query.

I think you meant `equals` and not `=` in the LINQ for `join` and `==` and not `=` for the `where`. — NetMage, Jul 19 '18 at 21:48

how to join 2 tables with lambda expression c#

1 Answers1