     <f:facet name="header">  
                                    <h:outputLabel value="Purchase No"/>
                                </f:facet> 
                                <h:outputLabel value="#{b1.billedBill.deptId}" >
                                </h:outputLabel>
                            </p:column>

                            <p:column headerText="Cancelled At">
                                <f:facet name="header">  
                                    <h:outputLabel value="Cancelled At