json support for composites in upcoming 9.2

[jan zimmek <jan.zimmek@xxxxxx>]

hi,

i am looking into json support of the upcoming 9.2 release and have a question about the row_to_json function. is there a way to specify the column aliases of a nested composite row without creating a custom type ?

here is an example:

select
  row_to_json(t1)
from (
  select 
    'joe' as username, 
    row(1, 'prj1') project
) t1;

the output is:

{"username":"joe","project":{"f1":1,"f2":"prj1"}}

i want the output to be:

{"username":"joe","project":{"project_id":1,"project_name":"prj1"}}

i thought of something like this:

select
  row_to_json(t1)
from (
  select 
    'joe' as username, 
    (select * from (values(1, 'prj1')) as project(project_id, project_name)) as project
) t1;

but this fails with "ERROR: subquery must return only one column".


any help would be really appreciated.

regards
jan zimmek
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