Ian Barwick wrote:
Workaround / solution to produce consistent results is to move the
"ORDER BY 1" to the main SELECT clause:
SELECT 1 AS id , 2 AS tmpl_id
WHERE FALSE
UNION
SELECT * FROM
(SELECT 2 AS id, 96 AS tmpl_id
UNION
SELECT 3 AS id, 101 AS tmpl_id
) tmpl
WHERE tmpl_id IS NOT NULL
ORDER BY 1
(The full version of this query in its original form is in production
on 8.2 and 8.3 versions and I am confident it has always produced
consistent results. It is used to select the appropriate template for
pages on a website and someone would have noticed long before now if
it was serving up the wrong template).
Note I'm not sure whether this is a bug, or whether the assumption
made for the original query (that the row order returned by the
subquery would be carried over to the main part of the query) is
incorrect but just happened to work as expected pre-8.4.
I don't believe it's a bug - the assumption is one you're not entitled
to make. Your "workaround" is the correct solution, ISTM.
cheers
andrew
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