Aliases with "Union"

[usbo]

SQL:

select a.A as M
from tab1 a
union all
select b.B as M
from tab2 b

parser = Parser(SQL)
print(parser.columns_dict, parser.columns_aliases)

Result:

{"M": "tab1.A"}

Expected:

{"M": ["tab1.A", "tab2.B"]}

[trevdoz]

ditto...to solve this I had to hack together something that does this:

• breaks up query into each query type ("WITH" queries, subqueries and the main select query)
• for each query, if "UNION" in query split on union type ("UNION" or "UNION ALL")
• parse those select statements individually and merge them into a single 'union_column_aliases_dict'
• update the original columns_aliases attribute with this 'union_column_aliases_dict'

definitely not 'Pythonic' and wish it could be handled automatically by this library but SQLToken.is_potential_column_alias stops any 'updates' from happening if the parser sees the same alias twice in the query