Feat/polyfill condition tables

[gwillz]

This adds a query modifier for any fields that don't already have a table.column form.

It takes the table name, or alias, from the from() modifier and simply tacks it onto any fields that are I guess 'naked'.

This applies to:

• select() fields
• where() conditions
• join() conditions
• having() conditions
• orderBy()
• groupBy()

Example

$query = $pdb->find('users AS user')
  ->fixTables()
  ->select('name', 'other.field')
  ->innerJoin('others AS other', ['other.user_id = user.id'])
  ->where(['OR' => [
     'other.status' => 'deleted', 
     'date_deleted' => null,
  ]])
  ->orderBy('record_order');

produces:

SELECT user.name, other.field
FROM users AS user
INNER JOIN others AS other
  ON other.user_id = user.id
WHERE other.status = 'deleted'
  OR user.date_deleted IS NULL
ORDER BY user.record_order

Regarding conditions

It only performs this modification on the left-hand side of an expression. If the right-hand is missing the table then there's not much we can do. Or is there?

I'm not sure about string conditions either. They're quite an weird edge-case altogether.

Some testing will clarify all of this.

Draft because:

• fixTables() is a terrible name
• no tests!
• orderBy()/groupBy() should check against the select() aliases to prevent accidentally prefixing an alias