On 08/04/2016 16:31, Michael Nolan wrote:
> I'm looking at the possibility of using JSON as a data exchange format
> with some apps running on both PCs and Macs. .
>
> The table I would be exporting has a lot of NULL values in it. Is
> there any way to skip the NULL values in the row_to_json function and
> include only the fields that are non-null?
You could use a CTE to filter out the nulls (not tested - I haven't used
JSON in PG (yet!)):
with no_nulls as (
select ... from my_table
where whatever is not null
)
select row_to_json(....) from no_nulls;
One of us is confused. I'm reading this as "I want a row_to_json" call to generate objects with different keys depending on whether a given key would have a null - in which case exclude the key.
I
think one would have to simply allow row_to_json to populate the keys with null values and then post-process them away:
json_strip_nulls(row_to_json(...))
David J.
