using (OleDbConnection OleConn = new OleDbConnection(sConnectionString))
  {
  OleConn.Open();
  string sql = "SELECT * FROM [总$] ";
  OleDbDataAdapter OleDaExcel = new OleDbDataAdapter(sql, OleConn);
  dtt.TableName = reportName;
  OleDaExcel.Fill(dtt);
  OleConn.Close();
  OleConn.Dispose();
  }   

datarow[] dr dtt.select("F1>='2011/1/1' AND F1<='2011/1/2'");


DataTable newDt = new DataTable();

Foreach(DataRow dr in drs[])
{
newDt.ImportRow(dr);
}

------解决方案--------------------
貌似excel中的排序有点小问题,大概是这样的 1,11,12,13,14,15,16,17,18,19,2,20,21,22  他的2会排在19后面20前面,貌似是格式的问题,还要在确认一下

------解决方案--------------------
using (OleDbConnection OleConn = new OleDbConnection(sConnectionString))
 {
 OleConn.Open();
 string sql = "SELECT * FROM [总$] ";
 OleDbDataAdapter OleDaExcel = new OleDbDataAdapter(sql, OleConn);
 dtt.TableName = reportName;
 OleDaExcel.Fill(dtt);
 OleConn.Close();
 OleConn.Dispose();
 }  

datarow[] dr dtt.select("F1>='2011/1/1' AND F1<='2011/1/2'");


DataTable newDt = new DataTable();

Foreach(DataRow dr in drs[])
{
newDt.ImportRow(dr);
}


然后把 你的datatable中的时间格式改了不就ok了