Re: Concatenating NULL with JSONB value return NULL

On Sun, Dec 18, 2016 at 6:08 PM, John R Pierce <pierce(at)hogranch(dot)com> wrote:

> On 12/18/2016 2:52 PM, Jong-won Choi wrote:
>
>>
>> I have a NULL-able JSONB type column and want to perform upsert,
>> concatenating with the existing value.
>>
>
> NULL does not mean 'NO' value in SQL it means UNKNOWN value. sort of like
> the 'indeterminate' in math.
>
> maybe you want a NOT NULL json value that you set to '' or something when
> its empty.
>
>
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> john r pierce, recycling bits in santa cruz
>
>
>
>
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Have you tried using CASE?

INSERT INTO Fan (oid, campaigns, facts) VALUES (189,'{"campaign-id":
"12345"}','{"attended": false}')
ON CONFLICT (oid)
DO UPDATE SET campaigns = EXCLUDED.campaigns,
CASE WHEN fan.facts is NULL
THEN facts = EXCLUDED.facts
ELSE facts = fan.facts || EXCLUDED.facts
END
RETURNING *;

--
*Melvin Davidson*
I reserve the right to fantasize. Whether or not you
wish to share my fantasy is entirely up to you.