Thom Brown wrote:
2009/12/15 Pavel Stehule <pavel.steh...@gmail.com <mailto:pavel.steh...@gmail.com>>

    Hello

    I am looking on new feature - ORDER clause in aggregate, and I thing,
    so we are able to effectively implement some non standard, but well
    known aggregates.

    a) function median - it is relative frequent request - with usually
    slow implementation

    b) function listagg (it is analogy of group_concat from MySQL) - it
    should simplify report generating and some other

    What is your opinion? Do you like to see these functions in core?



I'm probably missing the point here, but when I originally saw MySQL's group_concat function, I found it odd that it featured ordering functionality. Shouldn't the order by determined by the query itself? Otherwise it's almost as if its separating the relationship between the result column and the resultset.

For xmlagg in particular, it is quite useful to be able order the results. And sorting the query doesn't work for ordering the agg unless you do it in a subquery. Oracle has this functionality and it is quite handy. It would be nice to see listagg with the option to order as well.

Scott

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