select  distinct * from 表名

DataTable  dt=db.GetDt("select * from 表名");//獲得datatable
DataView dv = new DataView(dt);//虛擬視圖吧，我這么認為
DataTable dt2 = dv.ToTable(true, "name,age,hobby");

dv.ToTable(true, "name,age,hobby");