SqlCommand运行一个正确的sql语句，查询结果与数据库中的查询结果不一致？

Question

sql语句如下：
SELECT DISTINCT organization_name, (SELECT C FROM [教基1001] as x where x.A = 18 AND a.organization_no = x.organization_no) as contact
,(SELECT C FROM [教基1001] as y where y.A = 19 AND a.organization_no = y.organization_no) as contactduty
FROM [教基1001] as a
ORDER BY gather_organization_no, organization_no;

在数据库中结果是正常的：

使用该sql语句的代码如下：
string sqlStr = string.Format(@"SELECT DISTINCT organization_name, (SELECT C FROM [教基1001] as x where x.A = 18 AND a.organization_no = x.organization_no) as contact
,(SELECT C FROM [教基1001] as y where y.A = 19 AND a.organization_no = y.organization_no) as contactduty
FROM [教基1001] as a
ORDER BY gather_organization_no, organization_no;");

            List<DuDaoSchool> lists = new List<DuDaoSchool>();
            if (con.State == ConnectionState.Closed)
            {
                con.Open();
                SQLiteCommand com = new SQLiteCommand
                {
                    Connection = this.con,
                    CommandText = sqlStr,
                    CommandTimeout = 60 * 20,
                    CommandType = CommandType.Text
                };
                SQLiteDataReader rdr = com.ExecuteReader();

                while (rdr.Read())
                {
                    DuDaoSchool entity = new DuDaoSchool
                    {
                        Name = rdr["organization_name"].ToString(),
                        Contact = rdr["contact"].ToString(),
                        ContactDuty = rdr["contactduty"].ToString()
                    };
                    lists.Add(entity);
                }
            }

但是运行的结果，除了organization_name是正常的，另外两列都变成0了：

请问这是什么原因？问题出在哪？

Answer 1

1.断点跟，把sqlStr的内容放到数据库里去执行，看到底是什么，是否自己拼接sql语句的过程有问题
2.把读数据库的代码注释掉，直接给DuDaoSchool 赋值，看结果是什么，是否自己类封装的有问题，没有正确赋值
3.以后遇到此类问题，一步一步的排除，反正一共就这么几部分，先找到问题到底出在哪一步，再说如何解决