Is there any way I can import a shapefile into QGIS, then run spatial SQL queries against it?
I can obviously use ogr2ogr -sql to do this, but I have to import the output into QGIS each time to look at it, which is a pain.
It would be great if I could just import the shapefile into QGIS, then run SQL against it and see the results instantly.
You can use a virtual layer. Load your Shapefile in QGIS, then go to Layer / Add Layer / Add-Edit Virtual Layer. Type the SQL you want.
For instance, if your shapefile is named myshp and has attribute test you can query as:
select * from myshp a
where a.test = 1234;
Or you can make a spatial query using the geometry field:
select * from myshp
where st_intersects(geometry, make_point(1,2));
