Resolution:
If you need to sort only the first attribute of the selected attributes, specify order attribute as follows:

&ltselect novalue='default' order='1'>
    &lttable source='sql'>
        &ltliteral&gtLNA_PRICE_SEGMENT/PRODUCTID</literal>
        &ltliteral&gtLNA_PRICE_SEGMENT/SHORTDESC</literal>
</table>
</select>

Also, please note that the sorting precedence is in the following order

1. Numbers
2. Strings starting with capital case letters
3. Strings starting with small case letters

If you have any further questions please contact Tibco Support.