You can learn about colspan and rowspan here:
https://www.computerhope.com/issues/ch001655.htm
One quirk, if, in your example above, you have three columns and 6 rows, and you want to span the three columns and two rows, you will find the rows collapse into one row (because there are no other columns to the right with cells in to support the structure).
For your example, the approach I have taken above to set the height of the top cell is the best way. If, as I expect, you have many more columns to the right of the three you want to span, then you can do this:
WITHOUT colspan or rowspan
WITH colspan and rowspan
Titulo,a,b\n
d,e\n
8,12,5,x,y\n
13,19,7,x,y\n
20,22,3,x,y\n
23,29,7,x,y
You need to look carefully at the data you provide for the six cells you want to combine!
Here is a visual example using html/css
<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
<head>
<title>Demo</title>
<style>
table,td {
border: 1px solid black;
}
table {
width:50%;
margin: auto;
}
td {
height:50px;
text-align: center;
}
</style>
</head>
<body>
<br><br><br>
<table>
<tr>
<td colspan="3" rowspan="2" style="background-color:powderblue">Titulo</td>
<td>a</td>
<td>b</td>
</tr>
<tr>
<td>c</td>
<td>d</td>
</tr>
<tr>
<td>8</td>
<td>12</td>
<td>5</td>
<td>x</td>
<td>y</td>
</tr>
<tr>
<td>13</td>
<td>19</td>
<td>7</td>
<td>x</td>
<td>y</td>
</tr>
</table>
</body>
</html>
