Question

我需要从表CUSTOMER获取客户名称，并从表ACCOUNT中获取余额。我加入两个表但无济于事。请注意，如果要连接两个包含相同列名的表，则必须使用对多个表中存在的列名的前缀引用，其中包含表名或表别名和句点（。），或者错误消息ORA- 00918列模糊定义将显示。

select c.cfirst, c.clast, a.balance
from customer c, account a
where c.social = a.social AND social in (select social from account where social in (select social
from trans where dotrans > '04/01/2016' and means_of_trans = 'credit'));

Answer 1

您必须为社交列添加alias名称。因为这两个表都有这个列。

试试这个：

select c.cfirst, c.clast, a.balance
from customer c, account a
where c.social = a.social AND a.social in (select social
                                         from account
                                         where social in (select social

                                                        from trans
                                                        where dotrans > '04/01/2016' and means_of_trans = 'credit'));

Answer 2

无需再次对帐户表进行子查询，因为您只需使用转换表中的社交值检查帐户表中的社交值。

  select c.cfirst, c.clast, a.balance
    from customer c, account a
    where c.social = a.social 
    AND a.social in ( select social
                      from trans where dotrans > '04/01/2016' 
                      and means_of_trans = 'credit'
                     );

如何使用子查询连接两个表

2 个答案: