查詢SQL到Lambda表達式

Question

希望您能幫到我。

我想使用C＃中的lambda表達式從SQL轉換此查詢：

select  
    a.Descripcion 
from 
    pb.MantenimientosTipos a
where 
    a.activo = 1 and
    a.idSegmento in (select b.idSegmento 
                     from pb.MaquinasRelSegm b 
                     where b.idMaquina = 67)

我怎樣才能做到這一點？

我有兩個selectList，“ a”和“ b”，selectList“ a”是來自表b的按參數篩選的列表，而selectList“ b”是來自表b的按SelectList“ a”篩選的列表

private SelectList a (bool agregarTodo = false)
{
    var segmentos = pb.MaquinasRelSegm.Where(x => x.idMaquina == MaquinaId).Select(x => x.Segmentos).ToList();

    if (agregarTodo)
    {
        segmentos.Add(new PB.Domain.Entities.Segmentos { idSegmento = 0, Descripcion = "Todos" });
    }

    return new SelectList(segmentos, "idSegmento", "Descripcion");
}       

private SelectList b (byte idSegmento, bool agregarTodo = false)
{
    var tipos = pb.MantenimientosTipos.Where(x => x.idSegmento == idSegmento && x.Activo).ToList();
    if (agregarTodo)
    {
        tipos.Insert(0, new PB.Domain.Entities.MantenimientosTipos { idTipoMTTO = 0, Descripcion = "Todo" });
    }

    return new SelectList(tipos, "idTipoMTTO", "Descripcion")
}

我只想在此SQL查詢中放入一個selectList

這是SQL SERVER https://drive.google.com/file/d/0BzpCEYwGGpogRGRaOVNXTDBrTWc/view?usp=sharing中的關系

Answer 1

感謝您的圖表。

嘗試使用它（假設pb是EF上下文）：

var segmentoIds = pb.MaquinasRelSegm
    .Where(a => a.idMaquina == 67)
    .Select(a => a.idSegmento)
    .ToList();

var description = pb.MantenimientosTipos
    .Where(a => a.Activo && segmentoIds.Contains(a.idSegmento))
    .Select(a => a.Description);