orcale表关联查询，关联字段的数据重复了

Question

select b.idbranch,count(case when b.billmode = '1' then b.accno end) as issueBill
from param_bank a,accnomaindata b,ebankdata c
where b.accno = c.accno and b.idbranch=a.idbank
group by b.idbranch

因为ebankdata表里的accno字段是有重复的，关联查询的统计的数目不对
使用左连接查询写的语句报错了
select b.idbranch,count(case when b.billmode = '1' then b.accno end) as issueBill
from param_bank a,ebs_accnomaindata b,ebs_ebankdata c
ebs_accnomaindata b left join (select accno from ebs_ebankdata group by accno ) d on (b.accno=d.accno )

where b.idbranch=a.idbank and d.accno = c.accno

Answer 1

做出修改，左查询
select b.idbranch,count(case when b.billmode = '1' then b.accno end) as issueBill
from param_bank a,ebs_ebankdata c,
ebs_accnomaindata b left join (select accno from ebs_ebankdata group by accno ) d on (b.accno=d.accno )

where b.idbranch=a.idbank and d.accno = c.accno
group by b.idbranch
查询结果居然一样