Surround boolean expressions with parentheses

Better fidelity.

Signed-off-by: Stephen Celis <stephen@stephencelis.com>
Add SELECT DISTINCT helper

Signed-off-by: Stephen Celis <stephen@stephencelis.com>
Reorganize ASC/DESC

They're main computer variables, not Expressible extension material.

Signed-off-by: Stephen Celis <stephen@stephencelis.com>
Use helpers wherever possible

Signed-off-by: Stephen Celis <stephen@stephencelis.com>