Question : Order by within order by

I have this query below. I need to have an ORDER BY transac_id from ORDER BY t.idinvoice


SELECT
<output name="c.name" title="Name"/>,
<output name="c.reference" title="Reference" />,
<output name="t.transac_id" title="Transaction" />,
<output name="time" />AS Month,
<output name="t.idinvoice" title="Invoice ID" />,
<output name="t.idpayment" title="Payment ID" />,
<output name="amount" Xrenderer="Ext.util.Format.change" />,
<output name="t.user" />
FROM transac t
LEFT JOIN address a ON a.idaddress = t.idaddress
LEFT JOIN client c ON c.idclient = a.idclient
WHERE a.idaddress = '<input name="idaddress" />'
ORDER BY t.idinvoice

Answer : Order by within order by

Just list the columns to sort by in the order you want them sorted.

ORDER BY transac_id, t.idinvoice