SQL syntax does not support composite keys

[hgldarby]

From the readme

# We start with creating two tables:
left = Table()
left.add_column('number', int, allow_empty=True, data=[1, 2, 3, 4, None])
left.add_column('color', str, data=['black', 'blue', 'white', 'white', 'blue'])  # US english color.

right = Table()
right.add_column('letter', str, allow_empty=True, data=['a', 'b,', 'c', 'd', None])
right.add_column('colour', str, data=['blue', 'white', 'orange', 'white', 'blue'])  # Queens english.

# Now this wont work:
left_join = left.left_join(right, keys=['colour'], columns=['number', 'letter'])

# Because keys need to match `colour` with `color`

A possible fix could be a list containing a tuple of keys where index 0 indicates the left column and index 1 indicates the right.

[root-11]

solved in 37928a4
packaged as https://pypi.org/project/tablite/2020.11.3.53696/
readme updated in 39e2def

[root-11]

@hgldarby Please review and close ticket.