Re: [Fwd: Re: no ORDER BY in subselects?]

At 09:20 20/09/00 -0700, Josh Berkus wrote:
>Ooops, posted this to Phillip rather than the list, sorry Phillip ...
>
>Folks,
>
>Philip Warner wrote:
>> 
>> At 15:23 20/09/00 +0200, Louis-David Mitterrand wrote:
>> >
>> >ERROR:  parser: parse error at or near "order"
>> >
>> >Aren't ORDER BY clauses allowed in subselects?
>> >
>> 
>> It is a very very sad fact, but, no, they're not.
>
>Hmmmm ... can't say as I've ever seen an ORDER BY in a subselect before.
>Why would you want one?
>

The main reason I use them is to find the 'next' or 'previous' record in a
list (eg. next date, next ID). eg.
 select <whatever>, (select ID from table where id > this.id  order by id asc limit 1) as next_id ...

OR
 select <whatever>, (select Start_Date from table where Start_Date >
this.Start_Date Order By Start_Date asc limit 1) as End_Date


>And if you do want one, Louis-David, you can always use a temporary
>table as previously described.

It is A LOT less clean.

The fact that Dec RDB, Oracle and SQL/Server all allow it probably means
that there is a reasonable user base out there who think it's a good idea.


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