with t as (select id,
birthday,
identification,
substring(identification, 7, 8),
concat_ws('-', substring(substring(identification, 7, 8), 1, 4),
substring(substring(identification, 7, 8), 5, 2),
substring(substring(identification, 7, 8), 7, 2)
) as a
from app_public.users
where
identification is not null
and
identification != ''
)
UPDATE app_public.users t1
SET birthday = t.a
FROM t
WHERE t1.id = t.id;
-- select * -- from t;