Clipping polygon layer to another polygon layer based on matching attributes using QGIS?

Question

Working in QGIS, I have two polygon layers:

• Building Footprint Polygon Layer
• Parcel Polygon Layer

These two layers have a matching field in the attributes known as "Parcel Number". I would like to clip the building footprint features to be within the parcel polygon features based on matching parcel numbers. So if I have a building footprint feature that overlaps two parcel polygons, I would like to clip the building footprint to be within the parcel polygon that has the same parcel number as the building footprint.

Answer 1

QGIS3.0+

Let us assume we have a buildings layer (orange polygons: A, B, C) which is linked to another layer parcel (gray polygons: 101, 102, 103) by Parcel_Num attribute field.

We can use Geometry by Expression tool in Processing Toolbox | Vector geometry.

Click on the large Epsilon mark to open an expression dialog window:

Expression is:

intersection($geometry, geometry(get_feature('parcel', 'Parcel_Num', "Parcel_Num")))

And we will get red dashed polygons shown in a picture below, in which we can visually confirm A - 102, B - 101, C - 103 pairs.