2014-06-05 18:52 GMT+02:00 Thomas Mueller <[email protected]>:

> Hi,
>
> H2 supports user defined aggregate functions.
>

That's great, I wasn't aware of that! Off to our roadmap with that
<https://github.com/jOOQ/jOOQ/issues/3320>


> However, the "order by" syntax is not currently supported for those.
>

Note that if you want to delve into ordered aggregate functions, I suggest
you also consider hypothetical set function and inverse distribution
function support. The general syntax in those cases is

<ordered set function> ::=
    <hypothetical set function>
  | <inverse distribution function>

<hypothetical set function> ::=
    <rank function type> <left paren>
        <hypothetical set function value expression list> <right paren>
    <within group specification>

<within group specification> ::=
    WITHIN GROUP <left paren> ORDER BY <sort specification list> <right
paren>

<inverse distribution function> ::=
    <inverse distribution function type> <left paren>
        <inverse distribution function argument> <right paren>
    <within group specification>

Interestingly, the standard syntax for the above differs from the ARRAY_AGG
function, which is also standardised:

<array aggregate function> ::=
    ARRAY_AGG
        <left paren> <value expression> [ ORDER BY <sort specification
list> ] <right paren>

Instead of adding it to the roadmap, I think it's better to create an issue
> for it. That way, people can comment on it and add a patch.
>

Finally you're considering using the issue tracker! :-)
That would be a great moment to also think about moving to GitHub (and
migrating all issues over there)

Anyway, I'll create two Google Code issues for the above.

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