JOIN

Possible structures:

• String - just passed in to JOIN #{structure}
• Array with values(same order):
  • table representation
  • Hash
    • :on - conditions
    • :option - optional - contains Symbol or String of join type... rename to type?
• Array with combination of possible structures.

join: 'users u ON u.id = m.user_id'
join: ['users u ON u.id = m.user_id',
       'skills s ON u.id = s.user_id']
join: [[:user, :u], { on: 'rgl = 123' }]
# => 'JOIN users u ON rgl = 123'
join: [[[:user, :u], { option: :full, on: [:or, 'mrgl = 2', 'rgl = 22'] }],
       [:master, { on: ['z = 12', 'mrgl = 12'] }]]
# => 'FULL JOIN user u ON mrgl = 2 OR rgl = 22 JOIN master ON z = 12 AND mrgl = 12'

Need some meditations over it structure...