Query: Improve SQL for queries with left join that generate subqueries due to discriminator predicate #7689
Description
In 291a548 we started introducing subqueries to handle discriminator predicates in queries with LEFT JOINs. Currently we project all columns in the inner SelectExpression individually, we could switch to SELECT [inner_table].*
This makes for smaller SQL but will also help in the future once we stop materializing everything in LEFT JOIN queries