Ora 字符串转集合，集合转字符串，CLOB转char

Ora 字符串转集合，集合转字符串，转char，

select  CL_EDIAG,(SELECT DIAG_NAME  FROM CODE_DIAGNOSE WHERE  DIAG_CODE =CL_EDIAG  ) CL_EDIAGNAME,
    CL_CDIAG CL_CDIAGNAME,dbms_lob.substr((SELECT wmsys.wm_concat(DIAG_CODE)  FROM CODE_DIAGNOSE WHERE  DIAG_NAME   in (

SELECT REGEXP_SUBSTR(CL_CDIAG, '[^ ]+', 1, LEVEL) 
FROM DUAL 
CONNECT BY REGEXP_SUBSTR(CL_CDIAG, '[^ ]+', 1, LEVEL) IS NOT NULL

)

  ) ) CL_CDIAG
 from ip_register where reg_no='2020020200003'