Re: proposal sql: labeled function params - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: proposal sql: labeled function params
Date
Msg-id 162867790808152338h42b31d7bh80781565de655284@mail.gmail.com
Whole thread Raw
In response to Re: proposal sql: labeled function params  (Hannu Krosing <hannu@2ndQuadrant.com>)
Responses Re: proposal sql: labeled function params  (Peter Eisentraut <peter_e@gmx.net>)
List pgsql-hackers
2008/8/15 Hannu Krosing <hannu@2ndquadrant.com>:
> On Fri, 2008-08-15 at 14:54 +0200, Pavel Stehule wrote:
>> 2008/8/15 Peter Eisentraut <peter_e@gmx.net>:
>> > Am Thursday, 14. August 2008 schrieb Pavel Stehule:
>> >> I propose enhance current syntax that allows to specify label for any
>> >> function parameter:
>> >>
>> >> fcename(expr [as label], ...)
>> >> fcename(colname, ...)
>> >>
>> >> I would to allow  same behave of custom functions like xmlforest function:
>> >> postgres=# select xmlforest(a) from foo;
>> >>  xmlforest
>> >> -----------
>> >>  <a>10</a>
>> >> (1 row)
>> >
>> > Do you have a use case for this outside of XML?
>> >
>>
>> JSON and similar (custom) protocols
>
> why not use a format string, or any other separate (sub)language ?
>
> select json('[name:$1, age: $2]', name, age) from students;
>

because you have to write labels, where labels are equal with column
names. I would to add same comfort like SQL/XML functions.

Pavel


> ------------
> Hannu
>
>


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