sql 查询如何将结果集 输出为一段字符串？

文件id集合

文件表、

SELECT CONCAT('2323',(SELECT 'dsfsd'),'232323');

SELECT CONCAT('2323',(SELECT file_ids FROM img_words WHERE INSTR(toutiao_publisher_id_list,'232334')),'232323');

SELECT * FROM toutiao_file WHERE INSTR(( SELECT file_ids FROM img_words WHERE INSTR(toutiao_id_list,'232334')),id);

SELECT * FROM toutiao_file WHERE INSTR(
(
SELECT CONCAT(',',(SELECT file_ids FROM img_words WHERE INSTR(toutiao_id_list,'5655')),',')

),id);

SELECT * FROM toutiao_file WHERE INSTR((SELECT CONCAT(',',(SELECT file_ids FROM img_words WHERE INSTR(toutiao_id_list,'5435')),',') ),CONCAT(',',id,','));