Is there a way to create merged rows in a column of table in markdown files like ReadMe.md files?
Something like this:
No, this is not possible with GitHub-Flavored Markdown. As the spec explains (emphasis added):
The remainder of the table’s rows may vary in the number of cells. If there are a number of cells fewer than the number of cells in the header row, empty cells are inserted. If there are greater, the excess is ignored:
Of course, you can always fall back to raw HTML.
<table>
<thead>
<tr>
<th>Layer 1</th>
<th>Layer 2</th>
<th>Layer 3</th>
</tr>
</thead>
<tbody>
<tr>
<td rowspan=4>L1 Name</td>
<td rowspan=2>L2 Name A</td>
<td>L3 Name A</td>
</tr>
<tr>
<td>L3 Name B</td>
</tr>
<tr>
<td rowspan=2>L2 Name B</td>
<td>L3 Name C</td>
</tr>
<tr>
<td>L3 Name D</td>
</tr>
</tbody>
</table>
Try it yourself at https://jsfiddle.net/7h89y55r/