Re: jsonb_concat: make sure we always return a non-scalar value

On 9/9/15 12:03 PM, Oskari Saarenmaa wrote:
>>     andrew=# select '[1]'::jsonb || '{"a":"b"}';
>>          ?column?
>>     -----------------
>>       [1, {"a": "b"}]
>
> It looks wrong, but I'm not sure what's right in that case.  I think
> it'd make sense to just restrict concatenation to object || object,
> array || array and array || scalar and document that.  I doubt many
> people expect their objects to turn into arrays if they accidentally
> concatenate an array into it.  Alternatively the behavior could depend
> on the order of arguments for concatenation, array || anything -> array,
> object || array -> error.

That definitely doesn't sound like a good default.

It might be useful to have a concat function that would concatinate 
anything into an array. But if we don't provide one by default users 
could always create their own with json__typeof() and json_build_array().
-- 
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
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