Handle incompatible aggregate function and column in `@orderBy` directive

What problem does this feature proposal attempt to solve?

The orderBy directive provides 5 aggregate functions: AVG, MIN, MAX, SUM, COUNT. Not all of these functions can be used with all column types. This should be handled and should return a user friendly message in the response.

Specifically, AVG and SUM only work on numeric column types.

Which possible solutions should be considered?

Handling the specific issue mentioned with AVG and SUM on non-numeric types, could be solved simply with:

$relationModel = $builder->getModel()->$relation()->getRelated()->whereNotNull($relationColumn)->first();

if (! is_numeric($relationModel->$relationColumn) && in_array($aggregate, ['sum', 'avg'])) {
    throw new Error("$relation cannot be aggregated by SUM or AVG, please choose a different aggregate and try again.");
}

However, a more robust way of testing whether the aggregate function actually works with the specified column would be better.

Start by locating the @orderBy directive and the code that applies AVG, MIN, MAX, SUM, and COUNT to relation columns. Determine how to validate aggregate and column compatibility, then verify that incompatible AVG or SUM requests return a user-friendly response error without affecting valid aggregates.