How can I create the dynamic table beautifully? - html

Question

How can I set the table tag like this?
col1 col2 col3 col4
_____ _____ _____ _____
row1 | |_____|_____| |
row2 | |_____|_____| |
row3 | |_____|_____| |
row4 |_____|_____|_____|_____|
I know use the attribute rowspanto let the layout like this
as following my code:
<table>
<tr>
<th>number</th>
<th>type</th>
<th>quantity</th>
<th>amount</th>
</tr>
<tr>
<td rowspan="5">a</td>
<td>b</td>
<td>c</td>
<td rowspan="5">d</td>
</tr>
<tr>
<td>b</td>
<td>c</td>
</tr>
<tr>
<td>b</td>
<td>c</td>
</tr>
<tr>
<td>b</td>
<td>c</td>
</tr>
</table>
But in my case, the code is in the iterator of ruby each do method.
the items of col1 are all same, but items of col2 and col3 are all dynamic and col4 is the result of col3 calculating(sum).
I used to stupid way to layout the col1 by repeating the same value from row1 to row4 like this:
<table>
<tr>
<th>number</th>
<th>type</th>
<th>quantity</th>
<th>amount</th>
</tr>
<%#deals.each do |staff, deals|%>
<%if staff%>
<% #total_deal_type = deals.group_by(&:type).count%>
<%deals.group_by(&:type).each do |type, deals|%>
<tr>
<td><%=staff.number%></td>
<%case type%>
<%when "service1"%>
<%#d=staff.service1*deals.count%>
<td><%=type%></td>
<td><%= deals.count%></td>
<%when "service2"%>
<%#d2=staff.service2*deals.count%>
<td><%=type%></td>
<td><%= deals.count%></td>
<%when "service3"%>
<%#nc=staff.service3*deals.count%>
<td><%=type%></td>
<td><%= deals.count%></td>
<%when "service4"%>
<%#add=staff.service4*deals.count%>
<td><%=type%></td>
<td><%= deals.count%></td>
<%when "service5"%>
<%#bh=staff.service5*deals.count%>
<td><%=type%></td>
<td><%= deals.count%></td>
<%end%>
</tr>
<%end%>
<!--<p>amount:<%=#d.to_i+#d2.to_i+#nc.to_i+#add.to_i+#bh.to_i%></p>-->
<%end%>
<%end%>
</table>
So I want to merge the same value.
It's some way to do this?