A small new feature in SQL:2016 allows attaching a table alias to a
JOIN/USING construct:
<named columns join> ::=
USING <left paren> <join column list> <right paren>
[ AS <join correlation name> ]
(The part in brackets is new.)
This seems quite useful, and it seems the code would already support
this if we allow the grammar to accept this syntax.
Patch attached.
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Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services