here is the solutions.
Method 1 Bind Variables:
<dataQuery>
<sqlStatement name="Q1">
<![CDATA[
SELECT order_no, order_date, customer from orders
]]>
</sqlStatement>
<sqlStatement name="Q2">
<![CDATA[
SELECT payment_no, payment_date, amount
from payments where order_no = :order_no ]]>
</sqlStatement>
</dataQuery>
we just need to reference using colon (:) in 2nd query.
Method 2 Query Link:
<dataQuery>
<sqlStatement name="Q1">
<![CDATA[
SELECT order_no, order_date, customer from orders ]]>
</sqlStatement>
<sqlStatement name="Q2">
<![CDATA[
SELECT payment_no, payment_date, amount
from payments ]]>
</sqlStatement>
<link name="ORDER_LINK" parentQuery="Q1" parentColumn="ORDER_NO" childQuery="Q_2" childColumn="ORDER_NO"/>
</dataQuery>