避免在数据集重名 [英] Avoid duplicate names in a dataset
问题描述
我从表中获取数据,并绑定到一个标签,并在GridView下拉,但我想从过滤表中重复的名字,并指定相应的日期到DDL怎么可以这样做?或者是有什么其他选择?
私有数据集的get()
{
字符串SQL =选择编号,名称,RunDate从Historytable
SqlDataAdapter的大=新SqlDataAdapter的(SQL,CON);
DataSet的DS =新的DataSet();
da.Fill(DS);
返回DS;
}
保护无效GridView1_RowDataBound1(对象发件人,GridViewRowEventArgs E)
{ //什么code在这里?
}
如果您想找回您的HistoryTable只有唯一的名称,你应该使用关键字DISTINCT
SQL字符串=从Historytable选择不重复的名称;
不过,看到您的更新,我认为你应该查询更改为类似@dasblinkenlight的建议答案,如果你想在第一次约会每个名称
SQL字符串=选择闵(ID),名称,闵(RunDate)从Historytable组按名称;
或者(如果你想为每个名字的最后一天)
SQL字符串=选择马克斯(ID),名称,马克斯(RunDate)从Historytable组按名称;
I am fetching data from a table and binding to a label and Drop down in a gridview but i want to filter the duplicate names from the table and assign the corresponding dates to the DDL how can do this? or else is there any other alternative?
private DataSet get()
{
string sql = "select Id,Name,RunDate from Historytable";
SqlDataAdapter da=new SqlDataAdapter(sql,con);
DataSet ds=new DataSet();
da.Fill(ds);
return ds;
}
protected void GridView1_RowDataBound1(object sender, GridViewRowEventArgs e)
{
//what to code here?
}
If you want to get back only unique names from your HistoryTable you should use the keyword DISTINCT
string sql = "select DISTINCT Name from Historytable";
however, seeing your update I think you should change your query to something like the proposed answer of @dasblinkenlight, if you want the first date for each name
string sql = "select Min(ID), Name, Min(RunDate) from Historytable group by Name";
or (if you want the last date for each name)
string sql = "select Max(ID), Name, Max(RunDate) from Historytable group by Name";
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