HAVING bug in 6.4.2

HAVING appears not to recognise alias names for columns.

Examples:
** Using aggregate in HAVING clause works **
bray=> select p.brand,avg(s.free) as f from product as p, stock as s where
p.id = s.product group by p.brand having avg(s.free) > 100;
brand | f
------------+----
AVOCA | 660
BULK | 122
...
|5481
(14 rows)

** Using various kinds of column names in HAVING clause does not work **
bray=> select p.brand,avg(s.free) as f from product as p, stock as s where
p.id = s.product group by p.brand having f > 100;
ERROR: attribute 'f' not found
bray=> select p.brand,avg(s.free) as f from product as p, stock as s where
p.id = s.product group by p.brand having 2 > 100;
brand|f
-----+-
(0 rows)

bray=> select p.brand,avg(s.free) from product as p, stock as s where p.id =
s.product group by p.brand having 2 > 100;
brand|avg
-----+---
(0 rows)

Is this a known bug?

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
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