You see the parameterization of the box:

1. Selector type of Cartesian graph.
2. Column of the sentence with temporary value, in this case the month of the invoice the_month.
3. Filter by combo of the column the_year and thus be able to filter the graph by years.
4. SQL statement to execute, in this case:

<select>
    <columns>
        YEAR(invoicedate)  <alias name='the_year'/>,
        MONTH(invoicedate)  <alias name='the_month'/>,
        SUM(invoice.total) <alias name='the_total' />
    </columns>
    <from table='invoice'/>    
    <group>1,2</group>
    <order>1,2</order>
</select>

* Starting from the table of invoices and grouping by year and month.

5. In the series the column ' total' is added with the numerical value, in this case the total sales per month and year.

1. Selector type of Cartesian graph.
2. Column of the sentence with temporary value, in this case the month of the invoice the_month.
3. Filter by combo of the column the_year and thus be able to filter the graph by years.
4. SQL statement to execute, in this case:

<select>
    <columns>
        YEAR(invoicedate)  the_year,
        MONTH(invoice.invoicedate) <alias name='the_month' />,
        SUM(invoiceline.quantity * invoiceline.unitprice) <alias name='the_total' />,
        SUM(invoiceline.quantity * invoiceline.unitprice) - SUM(invoiceline.quantity * track.costprice) <alias name='the_profit'/>
    </columns>
    <from table='invoice'>
        <join table='invoiceline'>
            <on>invoice.invoiceid = invoiceline.invoiceid</on>
            <join table='track'>
                <on>invoiceline.trackid = track.trackid</on>    
            </join>
        </join> 
    </from>
    <group>1,2</group>
    <order>1,2</order>
</select>

* Starting from the table of invoices and grouping by year and month.

5. In the series the column ' the_total' is added with the numerical value, in this case the total sales per month and year.

The column ' the_profit' of line type is also added.