SQL Looping Index

Declare @tbl Table(order_idvarchar( -), datesdatetime)Insert @tbl(order_id,dates)Select 'A','2014-1-1' UnionSelect 'A','2014-2-1' UnionSelect 'A','2014-2-2' UnionSelect 'B','2014-1-1' UnionSelect 'C','2014-1-1' UnionSelect 'D','2014-1-1' UnionSelect 'D','2014-1-2' UnionSelect 'E','2014-12-1' UnionSelect 'E','2014-12-2' UnionSelect 'E','2014-12-3' Declare @index int,@count int,@row int,@item_order varchar( -),@current_order varchar( -)Select Identity(int,1,1) asId,order_id,dates,cast(0  as int) asRow_index into#tbl from @tbl Order  byorder_id,datesSelect @index=1,@row=1,@count=@ @rowcount while @row<=@countbegin    --First Cycle    if IsNull(@item_order,"')="'        Select     @item_order=order_id from#tblwhereId=@row    --already have to do loops    Else    begin        Select     @current_order=order_id from#tblwhereId=@row        if @current_order<>@item_order        begin            Set @index=1            Set @item_order=@current_order        End    End    --Update serial number    Update#tblSetRow_index=@index whereId=@row    Set @index=@index+1    Set @row=@row+1EndSelect *  from#tblDrop Table#tbl

SQL Looping Index