Good evening,
I am trying to SELECT ARRAY_AGG into an array from 2 tables.
But unfortunately here is what I get in PostgreSQL 10.5:
SELECT ARRAY_AGG(hashed)
FROM words_nouns
WHERE added > TO_TIMESTAMP(1539100913)
UNION
SELECT ARRAY_AGG(hashed)
FROM words_verbs
WHERE added > TO_TIMESTAMP(1539100913);
array_agg
-----------------------------------------------------
{noun1,noun2,noun3}
{verb1,verb2}
And thus I can not assign it to the _added variable in my custom function:
CREATE OR REPLACE FUNCTION words_get_added(
in_visited integer,
OUT out_json jsonb
) RETURNS jsonb AS
$func$
DECLARE
_added text[];
BEGIN
-- create array with words added to dictionary since in_visited timestamp
IF in_visited > 0 THEN
_added := (
SELECT ARRAY_AGG(hashed)
FROM words_nouns
WHERE added > TO_TIMESTAMP(in_visited)
UNION
SELECT ARRAY_AGG(hashed)
FROM words_verbs
WHERE added > TO_TIMESTAMP(in_visited)
);
IF CARDINALITY(_added) > 0 THEN
out_json := jsonb_build_object('added', _added);
END IF;
END IF;
END
And the assignment results in the error message:
www java[1082]: org.postgresql.util.PSQLException: ERROR: more than one row returned by a subquery used as an expression| Where: SQL statement "SELECT (| SELECT ARRAY_AGG(hashed) | FROM words_nouns | WHERE added > TO_TIMESTAMP(in_visited)| UNION| SELECT ARRAY_AGG(hashed) | FROM words_verbs | WHERE added > TO_TIMESTAMP(in_visited)| )"|PL/pgSQL function words_get_added(integer) line 7 at assignment
Please help me to modify my SELECT UNION so that I get just 1 row as result:
{noun1,noun2,noun3,verb1,verb2}
Regards
Alex
