DataReader 不返回行但存在数据答案

【问题标题】：DataReader returns no rows but data is presentDataReader 不返回行但存在数据
【发布时间】：2015-01-13 18:41:28
【问题描述】：

我正在尝试按月获取警报统计信息。这是我的 SQL 语句

SELECT datepart(year,incidentDate),datepart(month,incidentDate) ,COUNT(*) AS CNT 
From alarm_actions,alarm_licenses 
where licType = 'AR' and alarm_actions.alarmNo = ALARM_LICENSES.alarmNo and alarmCount > 0 and
ignoreAlarm = 0 and incidentDate between '5/1/12' and '7/31/14'
group by datepart(year,incidentDate) , datepart(month,incidentdate)
order by datepart(year,incidentDate)

当我在 SQL 2008R2 中执行此查询时，我得到 27 行，但是当我在 Visual Studios 中使用 SqlDataReader 时，我没有得到任何数据。 chartFrom 和 chartTo 是我用来获取日期的文本框。

string alarmCount = ("Select datepart(year,incidentDate) , datepart(month,incidentDate),COUNT(*) as cnt From Alarm_Actions,Alarm_Licenses Where licType = 'AR' and alarm_actions.alarmNo = alarm_licenses.alarmNo and alarmCount > 0 and ignoreAlarm = 0 and incidentDate between " + chartFromDate + " and " + chartToDate + "group by DATEPART(YEAR, incidentDate), DATEPART(MONTH,incidentDate) order by  DATEPART(YEAR, incidentDate)");
SqlDataReader dr = data.myDataReader(alarmCount);
while(dr.Read())
{
   //Do something
}

这是 myDataReader 的代码

 public SqlDataReader myDataReader(string mSQL) 
    {
        SqlConnection myConnection = new SqlConnection(connectionString);
        SqlDataReader myReader;
        SqlCommand myCommand1;
        try
        {
            myConnection.Open();
            //myCommand1 = new System.Data.OleDb.OleDbCommand(mSQL, myConnection);
            myCommand1 = new SqlCommand(mSQL, myConnection);

            //=============== 1/26/2012 =============
            //There have been errors running recently. I am increasing the timeout here
            myCommand1.CommandTimeout = 60000;

            myReader = myCommand1.ExecuteReader(CommandBehavior.CloseConnection);
            //return myReader;
        }
        catch (Exception e1)
        {
           MessageBox.Show("An error occurred retrieving the requested data\r\n\r\n" + mSQL + "\r\n\r\n" + e1.Message);
            myReader = null;
            try
            {
                string mSentBy = ConfigurationManager.AppSettings["emailSentBy"].ToString();
                string mSendTo1 = ConfigurationManager.AppSettings["emailSendTo"].ToString();
                string mSubject = ConfigurationManager.AppSettings["emailSubject"].ToString();
                string mHost = ConfigurationManager.AppSettings["emailHost"].ToString();
                string mSignon = ConfigurationManager.AppSettings["emailSignon"].ToString();
                string mPassword = ConfigurationManager.AppSettings["emailPassword"].ToString();
            }
            catch { }
        }
        finally
        {
            //myConnection.Close();
            myCommand1 = null;
            //myReader = null;
            myConnection = null;
            //myReader = null;
        }
        return myReader;
    }

谢谢你帮助我

我在日期字段中缺少 '。感谢大家花时间提供帮助

【问题讨论】：

你有什么异常吗？您能否发布整个代码、创建 Sql 连接的方式、构建执行它的命令等？
请贴出myDataReader()函数的代码。
可能与您的问题无关，但最好指定日期格式而不是进行隐式转换..
您能否在代码中发布查询的外观，以便我们查看这是否与格式问题有关？
我刚刚更新了它。 ChartFromDate 和 ChartToDate 是我用来获取日期的文本框。我输入了与上述查询相同的日期

标签： c# visual-studio sqldatareader

【解决方案1】：

我没有测试它，但我希望它对你有用：

SqlConnection con = new SqlConnection(connectionString);  

SqlCommand cmd = new SqlCommand();  
cmd.Connection = con;  
cmd.CommandText = "SELECT datepart(year,incidentDate), ......";  

con.Open();  

cmd.ExecuteNonQuery();  

SqlDataReader dr = cmd.ExecuteReader();

while(dr.Read())
{
   //Do something
}

con.Close();

【讨论】：