Hi,

What you could try is pass two parameters to your group_bconcat aggregate
function, the first one the value and the second the sort value. That way
the function can sort itself (which is what group_concat does as well).
That would look as follows: select group_bconcat(binData, orderColumn) from
...

Regards,
Thomas



On Fri, Jul 26, 2013 at 5:05 PM, Brian Craft <[email protected]> wrote:

> Here's the query with standard group_concat and cast:
>
> SELECT CAST(GROUP_CONCAT(`expScores` ORDER BY `i` SEPARATOR '') AS BINARY)
> AS `expScores` FROM `probes` LEFT JOIN `joins` ON `probes`.`id` = `pid`
>  LEFT JOIN `scores` ON `sid` = `scores`.`id` WHERE (`probes`.`eid` =
> (SELECT id FROM `experiments` WHERE (`experiments`.`file` = ?))) GROUP BY
> `joins`.`pid`
>
> The custom aggregate is a binary concat, group_bconcat which avoids the
> implicit cast in group_concat by concatenating primitive arrays. Works with
> BINARY and ARRAY types.
>
> The alternative is to do the concat in the application code, which perhaps
> I should do. It looks like the ORDER BY capability is hard-coded into the
> parser for group_concat, rather than being a generic option for aggregate
> functions.
>
> On Friday, July 26, 2013 12:34:13 AM UTC-7, Noel Grandin wrote:
>>
>> Do you have a more complete example of what exactly you are trying to do
>> with your custom aggregate?
>>
>> On 2013-07-26 00:34, Brian Craft wrote:
>> > I'm unable to use "order by" with a custom aggregate function. E.g
>> > with group_concat, you can do
>> >
>> > group_concat(`foo` order by `bar`)
>> >
>> > however this throws a syntax error with my aggregate function.
>> >
>>
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