Oracle查询中的子句

Question

IN子句在查询中不起作用

SELECT ITEM_GROUP_NAME,ELEMENTS ,(SELECT SUM(QUANTITY) qt
FROM SA_SALES_INVOICE SA 
WHERE ITEM_CODE  IN (T.elements  ) )  ta  
FROM ( 
    SELECT ITEM_GROUP_NAME, wm_concat(ITEM_CODE) as elements  
FROM   (SELECT A.ITEM_GROUP_NAME,B.ITEM_CODE 
FROM IP_ITEM_GROUP_SETUP A, IP_ITEM_GROUP_MAP B WHERE A.ITEM_GROUP