联盟都在DB2 SQL查询更新拳头表

Question

我真的卡在UNION ALL加入的顺序，下面是塞纳里奥

，如果我来逐个运行此查询我得到如下结果

1) Select salary as result from employee 
    where empno = '111628548' and seqno = 4 
    order by seqno Desc 

result 
------ 
$7000 
$3000 

2) Select descofemp as result from empdetail 
    where empno = '111628548' and seqno = 4 
    order by seqno Desc 

result 
------ 
very good employee 
good employee 

上述两导致字符串，所以列是相同的类型。 但是当我上面的两个查询与工会加入我得到像

With s1 as (Select salary from employee 
    where empno = '111628548' and seqno = 4 
    order by seqno Desc), 

s2 as (Select descofemp from empdetail 
    where empno = '111628548' and seqno = 4 
    order by seqno Desc 
) 
select * from s1              
Union ALL               
select * from s2 

Result 
------ 
$3000 
$7000 
very good employee 
good employee 

您可以在这里看到工资的顺序已经改变，我想verious的事情，但为什么顺序改变我不能够理解在UNION ALL中，是否有人知道或面对这个问题，如果是的话，你可以分享一些关于如何解决问题的信息。

预先感谢您。

问候 蒙娜丽莎

Answer 1

联盟确实不保证结果的排序。但是，您可以在订购信息中添加并使用：

With s1 as (Select salary as col, row_number() over (order by seqno desc) as seqnum 
    from employee 
    where empno = '111628548' and seqno = 4 
), 
s2 as (Select descofemp as col , row_number() over (order by seqno desc) as seqnum 
    from empdetail 
    where empno = '111628548' and seqno = 4 
) 
select col 
from (select * from s1              
     Union ALL               
     select * from s2 
    ) t 
order by seqnum