有表 student 和 course 。student中有course_ids。 现要把 course_ids 换成 course_names。
Select s.*, (
Select wm_concat(c.name)
From course c
Where c.id in (
SELECT REGEXP_SUBSTR(s.course_ids, '[^,]+', 1, LEVEL, 'i') AS d_ids
FROM DUAL
CONNECT BY LEVEL <= LENGTH(s.course_ids) - LENGTH(REGEXP_REPLACE(s.course_ids, ',', ''))+1)
)
)
From student s