SELECT ROWNUM,bmbaent,bmbasite, connect_by_root(bmaa001) root, bmba002,bmaa001,bmba003, LEVEL level1, sys_connect_by_path(LEVEL,‘∠‘) level2 FROM bmaa_t INNER JOIN bmba_t ON bmbaent=bmaaent AND bmbasite=bmaasite AND bmba001=bmaa001 AND bmba002=bmaa002 START WITH bmaaent=90 AND bmaasite=‘D‘ AND bmaa001=‘3102010165‘ AND bmaa002=9 AND bmaastus=‘Y‘ CONNECT BY bmaa001 = PRIOR bmba003 AND bmba006 IS NULL AND bmbaent=90 AND bmbasite=‘D‘ AND bmba002=9 ORDER BY ROWNUM
学习参考资料：
https://www.cnblogs.com/benbenduo/p/4588612.html
https://www.cnblogs.com/supermandy/p/7873233.html
原文：https://www.cnblogs.com/xiaoli9627/p/15185189.html