CTE with Query Builder

Hi,

I have some quite complex queries to which I would like to introduce some Common Table Expressions to improve performance and simplify.

The existing queries are already written using the query builder with the benefit this brings of built-in injection protection and simplicity for applying business logic to build the query. So I am quite keen to still utilise the query builder and not manually build SQL strings to execute directly as a query.

Can any one point me in the right direction of how I might go about extending the BaseBuilder (taking a quick glance I think that's the class I should be looking at) to enable CTE support.

I was thinking along the lines of a new function that accepts a parameter with the CTE in the form of an instance of the BaseBuilder or RawSql to add after a WITH clause at the start of the subsequent query.

I fear it might be beyond my understanding framework setup but you never know.

Thanks,

Luke