wrap the whole statement in another select
select col1, col2, col5, col6 from (
SELECT
col1, col2, col5, col6
FROM
table
WHERE
col2 = 'X'
UNION
SELECT
col3, col4, col5, col6
FROM
table
WHERE
col4 = 'X'
) as t
order by coalesce(col1, col3);
John Sidney-Woollett
Chris Green wrote:
It's not quite clear (to me at least) whether I can have a UNION and
an ORDER BY in a SELECT statement.
What I want to do is:-
SELECT
col1, col2, col5, col6
FROM
table
WHERE
col2 = 'X'
UNION
SELECT
col3, col4, col5, col6
FROM
table
WHERE
col4 = 'X'
ORDER BY
coalesce(col1, col3)
Is this valid syntax allowed by postgresql? (I'm not at the system
where postgresql is installed at the moment so I can't just try it)
col1 and col3 are both DATE columns. col2 and col4 are both
varchar(1).
I want the ORDER BY to order the result of the UNION.
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