The now archived discussion (started way back on 10g in 2010 --- https://community.oracle.com/message/12506211#12506211)
provided a solution to change default section orientation from row to column. Still no option exists today in 12g (as for as I can tell). Here's an updated
solution based on the original solution that uses Javascript to override the DOM that is generated by OBIEE 12g. You'll need to create
a static text box in your composite view with HTML enabled.
I've attached an alternate version the code that DOES WORK for my "section" enabled
Pivot table. Here's the "BEFORE" row oriented section layout in my analysis. Note: I use
the Samples Sales Catalog that is delivered with SampleApp. Section is by Year: 2013, 2014, 2015

Here is the "AFTER". In my static text box, I have a button that calls the function: transposePivotSection. This function transposes the row sections to
column sections (see below).

My Code:
<!--
<div id="myPivotContainer">
<table>
<tbody>
<tr>
<td>A</td>
</tr>
<tr>
<td>B</td>
</tr>
<tr>
<td>C</td>
</tr>
<tr>
<td>1</td>
</tr>
<tr>
<td>2</td>
</tr>
<tr>
<td>3</td>
</tr>
</tbody>
</table>
</div>
-->
<p>Click the button to transpose OBIEE pivot table sections from rows to column orientation.</p>
<button onclick="transposePivotSection()">Try it</button>
<script>
function transposeSimpleTable() {
var debug = 1;
var pivot_container_node = document.getElementById("myPivotContainer");
var table_node = pivot_container_node.getElementsByTagName('table');
var tbody_node = table_node[0].getElementsByTagName('tbody');
var trs = tbody_node[0].getElementsByTagName('tr');
var new_tbody = document.createElement('tbody');
var new_tr = document.createElement('tr');
for(var tr=0; tr < trs.length; tr++){
var new_td = document.createElement('td');
new_td.innerHTML = trs[tr].innerHTML;
new_tr.appendChild(new_td);
if (debug === 1) { console.log("Appended new td node");}
}
new_tbody.appendChild(new_tr);
table_node[0].replaceChild(new_tbody, tbody_node[0]);
}
function transposePivotSection() {
var debug = 1;
var toggle_section_row = true;
var ClassName = '';
var pivot_container_node = document.getElementsByClassName('PivotContainer');
var table_node = pivot_container_node[0].getElementsByTagName('table');
var tbody_node = table_node[0].getElementsByTagName('tbody');
var trs = tbody_node[0].getElementsByTagName('tr');
var new_tbody = document.createElement('tbody');
var new_tr = document.createElement('tr');
for(var tr=0; tr < trs.length; tr++){
if (toggle_section_row === true)
{
ClassName = 'PTSection';
}
else {
ClassName = 'PTChildPivotTable';
}
var PTnode = trs[tr].getElementsByClassName(ClassName);
if (PTnode.length !== 0 ) {
var cln_PTnode = PTnode[0].cloneNode(true);
new_tr.appendChild(cln_PTnode);
toggle_section_row = !toggle_section_row ;
}
}
new_tbody.appendChild(new_tr);
table_node[0].replaceChild(new_tbody, tbody_node[0]);
}
</script>