On 4/9/07, Tom Lane <[EMAIL PROTECTED]> wrote:
"Dann Corbit" <[EMAIL PROTECTED]> writes:
>> [EMAIL PROTECTED] On Behalf Of Lorenzo Thurman
>> I have three tables using date fields. I want to retrieve the oldest
>> date contained in the tables. Can someone show me an example of a query
>> that would do that?
> Just do a union and return the min
That's probably not enough detail for a newbie ...
SELECT min(x) FROM
(
SELECT min(datecol1) AS x FROM table1
UNION ALL
SELECT min(datecol2) AS x FROM table2
UNION ALL
SELECT min(datecol3) AS x FROM table3
) ss;
Exercise for newbie: which of the AS clauses are redundant?
they are all unnecessary :D
select least
(
(SELECT min(datecol1) FROM table1),
(SELECT min(datecol2) FROM table2),
(SELECT min(datecol3) FROM table3)
);
merlin
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