QGIS: intersect and filter in expression based filter

Question

I am trying to filter as part of an intersection but can't work out where to add the filter.

The intersection works fine intersects($geometry,aggregate('DSC_Roads','collect',$geometry))

But where can I add filter:="owner" in ('Private','Council') to only work on the 'DSC_Roads' layer when the owner column is in ('Private', 'Council')?

Answer 1

You're almoste there - add the filter as last argument of the aggregate() function. According to help for aggregate(), the syntax looks like:

aggregate(layer, aggregate, expression, [filter], [concatenator=’’], [order_by])

[] marks optional arguments

Thus the expression must look like:

intersects(
    $geometry,
    aggregate(
        'DSC_Roads',
        'collect',
        $geometry, 
        filter:="owner" in ('Private','Council')
    )
)

Only polygons with owner attribute value = 'Private' or 'Council' are selected: