Question

我有一个查询，我试图从查询特定ID的表中提取一些值。如果该值不存在，我仍然希望查询返回一个只有我正在寻找的ID值的记录。这是我到目前为止所尝试的内容。

Select attr.attrval, attr.uidservicepoint, sp.servicepointid 
From bilik.lssrvcptmarketattr attr 
Join bilik.lsmarketattrtype type on attr.uidmarketattrtype = type.uidmarketattrtype AND 
type.attrtype IN ('CAPACITY_REQUIREMENT_KW') and TO_CHAR( attr.starttime , 'mm/dd/yyyy')in ('05/01/2011') 
Right Outer Join bilik.lsservicepoint sp on attr.uidservicepoint = sp.uidservicepoint
Where sp.servicepointid in ('RGE_R01000051574382') Order By sp.servicepointid ASC

在这个例子中，我正在尝试寻找RGE_R01000051574382。如果表SP.servicepointid中不存在，我希望它仍然在一个记录中返回'RGE_R01000051574382'，其中包含我正在拉动的其他值的空值。通常情况下，当我运行时，我会一次提取大约1000个特定值。

如果有人对此有任何见解，我们将不胜感激。非常感谢！

Answer 1

如果我理解正确，您只需将WHERE子句移到JOIN子句中。

select attr.attrval,
    attr.uidservicepoint,
    sp.servicepointid
from bilik.lssrvcptmarketattr attr
join bilik.lsmarketattrtype type on attr.uidmarketattrtype = type.uidmarketattrtype
    and type.attrtype in ('CAPACITY_REQUIREMENT_KW')
    and TO_CHAR(attr.starttime, 'mm/dd/yyyy') in ('05/01/2011')
right outer join bilik.lsservicepoint sp on attr.uidservicepoint = sp.uidservicepoint
    and sp.servicepointid in ('RGE_R01000051574382')
order by sp.servicepointid

Answer 2

我认为你说你想恢复一条记录，填充了servicepointid列，但所有其他列都是null？

在这种情况下，请使用联盟。

select   ...your query without order by...
and      sp.servicepointid = 'RGE_R010000515743282'
union
select   null, null, 'RGE_R010000515743282'
from     dual
where    not exists (select 'x' from (...your query without order by...))

这是一个完整的例子：

create table test (id number, val varchar2(10));
insert into test (id, val) values (1, 'hi');

select   id,
         val
from     test
where    id = 1
union
select   1,
         null
from     dual
where    not exists (select   'x'
                     from     test
                     where    id = 1)

Oracle SQL：即使特定值不存在，也返回记录

2 个答案: