Question

如下所示;我如何实现fx.ftf_validitystartdate = ...这个行值，因为oracle不允许我这样做，如下所示

    select * from  acc_accounts acc
    join kp_paramcore p on
    acc.account_no = p.accountnum
    acc.suffix = p.suffixc
         LEFT JOIN ftf_rates fx
              ON p.maturestart = fx.ftf_vadealtsinir
             AND p.maturefinish = fx.ftf_vadeustsinir
             AND fx.statusrec = 'A'
             AND fx.currencycode = acc.currencsw_kod
             AND fx.status= 'A' 
  and  fx.ftf_validitystartdate= (SELECT MAX(ff.ftf_validitystartdate)
                                               FROM ftf_rates ff
                                              WHERE ff.status = 'A'
                                                AND ff.statusrec = 'A'
                                                AND v_CurrentDate BETWEEN ff.systemstartdate AND ff.systemfinishdate                                            AND ff.currencycode = acc.currencsw_kod
    )

Answer 1

如果将其切换为where子句，它应该可以工作：

select *
from acc_accounts acc join
     kp_paramcore p
     on acc.account_no = p.accountnum and
        acc.suffix = p.suffixc LEFT JOIN
     ftf_rates fx
     ON p.maturestart = fx.ftf_vadealtsinir and
        p.maturefinish = fx.ftf_vadeustsinir and
        fx.statusrec = 'A' and
        fx.currencycode = acc.currencsw_kod and
        fx.status= 'A'
 where fx.ftf_validitystartdate= (SELECT MAX(ff.ftf_validitystartdate)
                                 FROM ftf_rates ff
                                 WHERE ff.status = 'A' and
                                       ff.statusrec = 'A'
                                       p.v_CurrentDate BETWEEN ff.systemstartdate AND ff.systemfinishdate                                            AND ff.currencycode = acc.currencsw_kod
                                )

但是，您丢失了“左外连接”特征，因此您还需要添加：or fx.ftf_validitystartdate is null。我猜v_CurrentDate来自“p”。在列名之前使用表别名总是一个好主意。

但是，我怀疑子查询是否真的需要。仅当有多个记录满足子查询中的条件时才需要它。否则，我认为您只需将on子句更改为：

    ON p.maturestart = fx.ftf_vadealtsinir and
       p.maturefinish = fx.ftf_vadeustsinir and
       fx.statusrec = 'A' and
       fx.currencycode = acc.currencsw_kod and
       fx.status= 'A'and
       p.v_CurrentDate BETWEEN fx.systemstartdate AND fx.systemfinishdate

Answer 2

我使用CTE发布了解决方法，并仅在Oracle 11g中进行了测试。

To make test I create this schema：

create table t_a ( a int );
create table t_b ( a int);
create table t_c ( a int);

insert into t_a values (1);
insert into t_a values (2);
insert into t_a values (3);

insert into t_b values (1);
insert into t_b values (2);
insert into t_b values (3);

insert into t_c values (1);
insert into t_c values (2);
insert into t_c values (3);

此时我对此查询强制出错：

select * 
from t_a
left outer join t_b
  on t_a.a = t_b.a and
     t_b.a = ( select max( a )
             from t_c);

现在我用CTE重写查询：

with cte (a ) as (
   select a
   from t_b
   where t_b.a = ( select min( a )
             from t_c)
)
select * 
from t_a
left outer join cte
  on t_a.a = cte.a;

第二个查询返回正确的结果。

我用CTE重写你的查询：

with CTE as (
   select * from ftf_rates 
   where ftf_validitystartdate= (SELECT MAX(ff.ftf_validitystartdate)
                                 FROM ftf_rates ff
                                 WHERE ff.status = 'A'
                                      AND ff.statusrec = 'A'
                                      AND v_CurrentDate BETWEEN ff.systemstartdate 
                                      AND ff.systemfinishdate                   
                                      AND ff.currencycode = acc.currencsw_kod )

)
    select * from  acc_accounts acc
    join kp_paramcore p on
    acc.account_no = p.accountnum
    acc.suffix = p.suffixc
         LEFT JOIN CTE fx
              ON p.maturestart = fx.ftf_vadealtsinir
             AND p.maturefinish = fx.ftf_vadeustsinir
             AND fx.statusrec = 'A'
             AND fx.currencycode = acc.currencsw_kod
             AND fx.status= 'A'

注意，仅在Oracle 11g中测试过。参见@a_horse_with_no_name coment：

@danihp：CTE早在Oracle 11g之前就可以使用了（我认为它们是在9.1中引入甚至可能更早 - 但它们肯定是可在10.x中获得。 11.2引入了不需要的递归CTE 在这种情况下。 -

JOIN问题：更正要解决的SQL语句：ORA-01799：列可能不是外部连接到子查询

2 个答案: