SQLite supports complex expressions in group by columns - because of
course it does...
So we need to make sure that a column is created for this expression if
it doesn't exist already, and compute it, the same way we compute
pre-projections in the filter operator.
Fixes#3363Fixes#3366Fixes#3365
When adding tests for extensions, please follow these guidelines:
Tests that verify the internal logic or behavior of a particular extension should go into cli_tests/extensions.py.
Tests that verify how extensions interact with the database engine, such as virtual table handling, should be written
in TCL (see vtab.test as an example).
To check which extensions are available in TCL, or to add a new one, refer to the tester.tcl file and look at the extension_map.