Postgresql select in variable - sql

Question

I have two select
do $$
declare
uid text := 'b5974eec-7078-4ae7-923c-36af96905423';
my_output record;
Begin
-- Czas konwersji jednego ekstratku
SELECT sha256, (
SELECT timestamp
FROM public.tmask_mda02
WHERE uuid = uid
AND import = 'COMPLETED'
AND params = 'sha256 in')::timestamp - (
SELECT timestamp
FROM public.tmask_mda02
WHERE uuid = uid
AND export = 'COMPLETED'
AND params = 'sha256 out')::timestamp AS Interval
INTO my_output
FROM public.tmask_mda02
WHERE uuid = uid
AND params = 'sha256 out';
RAISE NOTICE 'Dlugosc_przetwarzania: %',my_output;
end $$;
Output is:
Dlugosc_przetwarzania:
(89b253f28435aea23fc68c042066e988d236f2f312583255c0352ea512701daf,-00:00:01.145)
SELECT DISTINCT uuid FROM public.tmask_mda02 WHERE export = 'COMPLETED' AND timestamp::text LIKE '2021-09-22%';
Output:
"02de41c7-488f-4dc9-bb33-b76b05426cde"
"0b82e409-e37f-4b34-a90a-c5b57d63d759"
"19d38112-efb0-4f67-97aa-493d0cf9a1a4"
"1e8e5745-6885-4e18-89a1-3c841efd48ac"
"223cfb85-b8eb-4ea1-8f14-fbd565f68344"
"27fcaadc-f487-4bfe-bee8-00b98375844b"
"311e0cc8-f398-4134-855f-b64631254af5"
"31f856fb-c814-4214-9612-1703f247de2b"
I need use select in variable uid:
do $$
declare
uid text := (SELECT DISTINCT uuid FROM public.tmask_mda02 WHERE export = 'COMPLETED' AND timestamp::text LIKE '2021-09-22%');
my_output record;
Begin
-- Czas konwersji jednego ekstratku
SELECT sha256, (
SELECT timestamp
FROM public.tmask_mda02
WHERE uuid = uid
AND import = 'COMPLETED'
AND params = 'sha256 in')::timestamp - (
SELECT timestamp
FROM public.tmask_mda02
WHERE uuid = uid
AND export = 'COMPLETED'
AND params = 'sha256 out')::timestamp AS Interval
INTO my_output
FROM public.tmask_mda02
WHERE uuid = uid
AND params = 'sha256 out';
RAISE NOTICE 'Dlugosc_przetwarzania: %',my_output;
end $$;