C# Datareader不使用选择上限和按上限分组
我正在尝试使用visual Studio 2015 Express中的c#从Microsoft SQL数据库获取数据。到目前为止,我使用的所有命令都有效。现在,我尝试使用SqlDataReader执行此命令:C# Datareader不使用选择上限和按上限分组,c#,sql,database,sqldatareader,C#,Sql,Database,Sqldatareader,我正在尝试使用visual Studio 2015 Express中的c#从Microsoft SQL数据库获取数据。到目前为止,我使用的所有命令都有效。现在,我尝试使用SqlDataReader执行此命令: SELECT UPPER(Company) FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0; 这是我的密码: //open the sql connection sqlConn.Open(); /* *
SELECT UPPER(Company) FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0;
这是我的密码:
//open the sql connection
sqlConn.Open();
/*
* This Sql command will get the field entries from all the selected fields and group them into selection groups.
*
* This is important because it gives a list of arguments to group docId's with.
*/
string selectCommand = "SELECT UPPER(Company) FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0;";
// Declare list for storing select groups. This will be returned
List <String> groupList = new List<string>();
// Set up table reader
SqlCommand sqlcmd = new SqlCommand(selectCommand, sqlConn);
dataRead = sqlcmd.ExecuteReader();
for (int i = 0; i < dataRead.FieldCount; i++)
{
Console.WriteLine("DATAREAD: '" + dataRead.GetName(i) + "' .");
}
while (dataRead.Read())
{
// select string for selecting groups
string select = "";
foreach (string colname in staple.fieldsToList())
{
// check for null
if(dataRead[colname] == DBNull.Value)
{
select = select + "NULL,";
}else{
select = select + dataRead[colname].ToString()
}
}
//store the select string in a list
groupList.Add(select);
}
return groupList;
因此,我检查了dataRead中的名称,发现公司所在的索引中有一个空字符串。我将selectCommand字符串中的上限(Company)替换为Company,它工作正常,因此不知何故,使用UPPER()命令会使DataReader在没有正确名称的情况下初始化
有人知道修复方法吗?尝试将名称重新输入:
SELECT UPPER(Company) AS Company ...
尝试将名称重新输入:
SELECT UPPER(Company) AS Company ...
尝试将名称重新输入:
SELECT UPPER(Company) AS Company ...
尝试将名称重新输入:
SELECT UPPER(Company) AS Company ...
将查询更改为:
SELECT UPPER(Company) As Company FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0;
如果在不应用别名的情况下应用sql函数(如UPPER
),则返回结果的(无列名)
将查询更改为:
SELECT UPPER(Company) As Company FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0;
如果在不应用别名的情况下应用sql函数(如UPPER
),则返回结果的(无列名)
将查询更改为:
SELECT UPPER(Company) As Company FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0;
如果在不应用别名的情况下应用sql函数(如UPPER
),则返回结果的(无列名)
将查询更改为:
SELECT UPPER(Company) As Company FROM MY_TABLE GROUP BY UPPER(Company) HAVING COUNT(*) > 0;
如果在不应用别名的情况下应用sql函数(如
UPPER
),则返回结果的(无列名)
很好!谢谢,很好用!谢谢,很好用!谢谢,很好用!非常感谢。