#### In this example, taking the box of invoice lines from the previous example, a link to the name of the song is added to the song master.

An adjustment is made on the SQL statement of the SQL-Table, adding the column 'track.trackid' so that it can be used as a value in the link.

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<select>
<columns>
track.trackid,
track.name,
invoiceline.unitprice,
invoiceline.quantity
</columns>
<from table='invoice'>
<join table='invoiceline'>
<on>invoiceline.invoiceid = invoice.invoiceid</on>
<join table='track' type='left'>
<on>invoiceline.trackid = track.trackid</on>
</join>
</join>
</from>
<where>
invoice.invoiceid = #invoiceid
</where>
<order>3 DESC</order>
</select>

The column 'trackid' is added to the output fields, but with the condition of hiding '1 == 1', because it does not matter if the column appears in the form.

Result: