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
– Camilo Terevinto, Commented Jul 19, 2018 at 18:09
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
– moi_meme, Commented Jul 19, 2018 at 18:14
You Can use Like this My example: stackoverflow.com/questions/30977089/asp-net-mvc-5-entity-join/… — Rajesh Kumar
– Rajesh Kumar, Commented Jul 19, 2018 at 18:15

Benjamin RD · Accepted Answer · 2018-07-19 21:58:14Z

1

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.

edited Jul 19, 2018 at 21:58

answered Jul 19, 2018 at 18:16

Benjamin RD

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1 Comment

NetMage Over a year ago

I think you meant equals and not = in the LINQ for join and == and not = for the where.

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