多条sql语句带条件查询拼接

同时查多张表拼接后并用json字符串显示在界面上：
示例代码如下：

public ActionResult GetApplyDetailInfos(string applyId)
{
     var AccountId = "";
     var ApplysData = $"select* from Applys where Id = '{applyId}'";
     using (var dbContext = new DBContext())
     {
         AccountId = dbContext.Database.SqlQuery<Apply>(ApplysData.ToString()).FirstOrDefault().AccountId;
     }
     var AccountsData = $"select* from Accounts where Id = '{AccountId}'";
     var BsApplysData = $"select* from BsApplys where ApplyId = '{applyId}'";
     var UsersData = $"select* from Users where ApplyId = '{applyId}'";
     var sb = new StringBuilder();
     using (var dbContext = new DBContext())
     {
         sb.Append(JsonConvert.SerializeObject(dbContext.SqlDataSet(ApplysData.ToString())));
         sb.Append(JsonConvert.SerializeObject(dbContext.SqlDataSet(AccountsData.ToString())));
         sb.Append(JsonConvert.SerializeObject(dbContext.SqlDataSet(UsersData.ToString())));
         sb.Append(JsonConvert.SerializeObject(dbContext.SqlDataSet(BsApplysData.ToString())));
     }
     return Content(sb.ToString());
}