ช่วยทีนะครับ เรื่อง subquery PL/SQL , JSON Array ครับ

CREATE OR REPLACE FUNCTION qa_returnjson(
	/*IN p_categoryid INT,
	IN p_iconid INT, */
	OUT dno VARCHAR,
	OUT datajson JSON
) RETURNS SETOF RECORD AS 
$BODY$
DECLARE
	v_data JSON;
	v_data2 VARCHAR :='1';
	iRowCk INT := 0;

BEGIN
	SELECT COUNT(category_name) INTO iRowCk
	FROM category;
	IF iRowCk <> 0 THEN 
		SELECT row_to_json(t) INTO v_data FROM(
			SELECT 'True' AS "Status" , 
			(
				SELECT array_to_json(
					ARRAY(
						SELECT row_to_json (tt) FROM (
								SELECT category_id AS "CateID", category_name AS "CateName",
								(
									SELECT array_to_json(
										ARRAY(
											SELECT row_to_json(ttt) FROM(
											 SELECT icon_id,icon_name FROM icon 
											) AS ttt
										)	
									)
								) AS "DatarowIcon"	

								FROM(
									 SELECT category_id,category_name FROM category WHERE category_active = TRUE ORDER BY category_id ASC
							) AS x
						) AS tt
					)
				)
			) AS "Datarow"
		) AS t;
	RETURN QUERY SELECT v_data2 AS iData, v_data AS "DataJson";
	END IF;
END;
$BODY$
LANGUAGE plpgsql;