字符串转数组：
(SELECT REGEXP_SUBSTR('34,56,-23', '[^,]+', 1, LEVEL, 'i') AS STR
FROM DUAL
CONNECT BY LEVEL <=
LENGTH('34,56,-23') - LENGTH(REGEXP_REPLACE('34,56,-23', ',', '')) + 1)
数组转字符串
select wmsys.wm_concat(cityname) from sys_city
where provinceid='29'