Is there a way to perform spatial queries on multiple layers in QGIS without going through an external database? I would like to perform SQL-like queries on layers imported in QGIS directly, but can't find a way to do so!
Basically, what I want is to do a "Select * From layer1 INTERSECT Select * From layer2 Where CONDITION"
I understand I can manually select features from a layer and then do a spatial query while checking the "use selected features" box, but I'd rather do everything in a query, as I have a lot to do and prefer not to fiddle with buttons.
The refFunctions proposed works great, but involves the field calculator; is there a way to simply select the features instead of modifying a table?
Maybe it's simply not possible directly.