var query = from a in tblEMAIL.AsEnumerable()
                    join b in tblUSER.AsEnumerable() on a.Field("MainKey") equals b.Field("MainKey")
                    join c in tblUSERTYPE.AsEnumerable() on a.Field("MainKey") equals c.Field("MainKey")
                    //join d in tblSCHOOL.AsEnumerable() on a.Field("MainKey") equals d.Field("MainKey")
                    select  new
                        {
                            EmailKey = a.Field("MainKey"),
                            EmailValue = a.Field("ProperValue"),
                            UserKey = b.Field("ProperKey"),
                            UserName = b.Field("ProperValue"),
                            UserTypeKey = c.Field("ProperKey"),
                            UserTypeName = c.Field("ProperValue"),
                            //SchoolKey = d.Field("ProperKey"),
                            //SchoolName = d.Field("ProperValue")
                        };
        if (query.Count() != 0)
        {
       
        }