ORA-00918columnambiguouslydefined

ORA-00918columnambiguouslydefined

11.2.0.1中同样的一个SQL能正常执行：
select -- 代金券收入
'VOUCHER' AS SUMMODE,
a.billingdate,
a.rdate,
a.storeroomid,
a.accountscode,
g.accountsname,
I.RELATED,--业务内容
CASE WHEN I.RELATED = 'HQ_billcheckout' THEN H.DICTIONARYCODE ELSE NULL END AS PAYMENTCODE,
CASE WHEN I.RELATED = 'HQ_billcheckout' THEN H.DICTIONARYNAME ELSE NULL END AS PAYMENT,--收款方式名称
CASE WHEN I.RELATED = 'HQ_billcheckout' THEN h.statistic_class ELSE NULL END AS statistic_class, --收款方式分类
nvl(a.debit,0)-nvl(a.credit,0) as tradeMoney,
0 as StandDealTotalm,
0 as DiscDealTotal,
0 as OtheDealTotal
from HQ_accountingbooks a
inner join m_coupon_grant d on a.bid=nvl(d.bid,d.cgid)
inner join HQ_accounts g on a.accountscode=g.accountscode
LEFT JOIN (SELECT A1.* FROM HQ_DATADICTIONARY A1 WHERE A1.DICTIONARYTYPE=1) H ON g.ACCOUNTSCODE=H.ACCOUNTCODE
inner join HQ_billcase_accounts i on d.billsubcase=i.billsubcase and a.accountscode=i.accountscode
where BILLSUBCASE = 5201;
在11.2.0.4中报错：
ORA-00918: column ambiguously defined
对比了下，两个数据库中所有对应的表表结构都一样，为什么在11.2.0.1中能正常执行，在11.2.0.4中执行不了？
发现这个SQL中有2个表中都有BILLSUBCASE这一列：
select BILLSUBCASE from HQ_accountingbooks;
select BILLSUBCASE from m_coupon_grant;
于是指定a.BILLSUBCASE = 5201;即解决。
看来11.2.0.4中对SQL的语法要求更严格。