SELECT bbb_id INTO OUTFILE 'c:/bbb_isnotnull_list.csv' FIELDS TERMINATED BY ',' LINES TERMINATED BY '\r\n' FROM v_tmp WHERE bbb_id IS NOT NULL ;

CREATE VIEW v_tmp AS SELECT t_aaa.id AS aaa_id ,t_bbb.id AS bbb_id FROM t_aaa LEFT JOIN t_bbb ON t_aaa.id = t_bbb.id ;