Sql查询到实体查询

Question

我对实体查询非常陌生，我想将此sql查询转换为实体查询：

select A1.PrID,A3.Pr_Nom, A1.MpID, A2.Mp_Designation, A1.PR_Mp_etat, A1.Pr_Mp_quantite
from Pr_Mp A1, MatierePremiere A2, Projet A3
where A1.MpID = A2.MpID
and A3.PrID=A1.PrID
and A3.Pr_Nom= 'projet1'

我想从这个查询得到的是检索Mp_designation和MpID（从表matierePremiere中检索数据）

这是我的表格：

public partial class MatierePremiere
    {
        public MatierePremiere()
        {
            this.Commandes = new List<Commande>();
            this.Pr_Mp = new List<Pr_Mp>();
        }

    public int MpID { get; set; }
    public string Mp_Designation { get; set; }
    public virtual ICollection<Commande> Commandes { get; set; }
    public virtual ICollection<Pr_Mp> Pr_Mp { get; set; }
}



public partial class Pr_Mp
    {
        public int PrID { get; set; }
        public int MpID { get; set; }
        public string Pr_Mp_etat { get; set; }
        public double Pr_Mp_quantite { get; set; }
        public virtual MatierePremiere MatierePremiere { get; set; }
        public virtual Projet Projet { get; set; }
    }

public partial class Projet
    {
        public Projet()
        {
            this.Personnel_Projet = new List<Personnel_Projet>();
            this.Pr_Mp = new List<Pr_Mp>();
        }

    public int PrID { get; set; }
    public string Pr_Nom { get; set; }
    public System.DateTime Pr_Date_Debut { get; set; }
    public System.DateTime Pr_Date_Fin { get; set; }
    public string Pr_Statut { get; set; }
    public Nullable<System.DateTime> Pr_Tps_Estime { get; set; }
    public Nullable<double> Pr_cout_Estime { get; set; }
    public string Pr_Adresse_Terrain { get; set; }
    public double Pr_Superficie_Terrain { get; set; }
    public string Tech_Cin_Directeur_Technique { get; set; }
    public string Tech_Cin_Responsable_projet { get; set; }
    public string Tech_Cin_Architecte_Pilote { get; set; }
    public System.DateTime created_date { get; set; }
    public virtual ICollection<Personnel_Projet> Personnel_Projet { get; set; }
    public virtual ICollection<Pr_Mp> Pr_Mp { get; set; }
}

我尝试了这个查询：

(from prMp in Pr_Mp 
  join mp in MatierePremieres 
    on prMp.MpID equals mp.MpID 
  join pr in Projets 
    on prMp.PrID equals pr.PrID 
where pr.Pr_Nom=="projetTest" 
select prMp.Pr_Mp_etat, mp.Mp_Designation, pr.pr_Nom)
.ToList()