Parse select item alias even without AS keyword

[orian]

ClickHouse allows to not use AS keyword when naming selected columns:

SELECT col1 AS one, col2 two
FROM tbl

Fix it.

[coveralls]

Pull Request Test Coverage Report for Build 13620153978

Details

• 14 of 14 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.06%) to 60.841%

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Totals
Change from base Build 13580367952:	0.06%
Covered Lines:	6541
Relevant Lines:	10751

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💛 - Coveralls

[git-hulk]

LGTM, thank you!