oracle实现类似split效果

SELECT *
FROM (
SELECT t.*,
regexp_substr(t.str, '[^,]+', 1, x.n) cc
FROM (
SELECT 'a,b,c,d' str FROM dual
UNION ALL
SELECT '11,223,44' FROM dual
) t,
(SELECT ROWNUM n FROM dual CONNECT BY ROWNUM <= 5) x

ORDER BY 1
)
WHERE cc IS NOT NULL

WITH t AS(
SELECT wm_concat(tt.str) str
FROM (
SELECT 'a,b,c,d' str FROM dual
UNION ALL
SELECT '11,223,44' FROM dual
) tt
)
SELECT t.str, regexp_substr(t.str,'[^,]+',1,ROWNUM) VALUE
FROM t
CONNECT BY ROWNUM <= LENGTH(regexp_replace(t.str,'[^,]+'))+1;