i.e. rails' ActiveRecord allows you to select columns easily in most cases:

    User.where(..) # all fields
    User.where(..).select(:name, :id) # only two of them
    joe.boards.select(:title)  # only one in join
    joe.boards.pluck(:title)   # only column value instead of full objects with one attribute set

You should also be able to setup the select as a default per-class, other than per query.

I suspect, I likely didn't understand your question, could you expand it?

    .only(… field list…)
    .defer(… fields to fetch on demand…)

It's really a PIA.

Recently, I've learned about http://jooq.org/ — not having checked in detail yet, it might be easier there.

http://www.sqlalchemy.org/