pgsql: Improve docs about using ORDER BY to control aggregate input ord

Started by Tom Laneabout 10 years ago1 messagescomitters

tgl@sss.pgh.pa.us

about 10 years ago

Improve docs about using ORDER BY to control aggregate input order.

David Johnston pointed out that the original text here had been obsoleted
by SQL:2008, which allowed ORDER BY in subqueries. We could weaken the
text to describe ORDER-BY-in-subqueries as an optional SQL feature that's
possibly unportable; but then the exact same statements would apply to
the alternative it's being compared to (ORDER-BY-in-aggregate-calls).
So really that would be pretty useless; let's just take out the sentence
entirely. Instead, point out the hazard that any extra processing in the
upper query might cause the subquery output order to be destroyed.

Discussion: <CAKFQuwbAX=iO9QbpN7_jr+BnUWm9FYX8WbEPUvG0p+nZhp6TZg@mail.gmail.com>

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/82eafabeaaf12231a85ed67bbf4eae698aacb1c9

Modified Files
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doc/src/sgml/func.sgml | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

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