聯盟都在DB2 SQL查詢更新拳頭表

Question

我真的卡在UNION ALL加入的順序，下面是塞納里奧

，如果我來逐個運行此查詢我得到如下結果

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 

上述兩導致字符串，所以列是相同的類型。 但是當我上面的兩個查詢與工會加入我得到像

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 

您可以在這裏看到工資的順序已經改變，我想verious的事情，但爲什麼順序改變我不能夠理解在UNION ALL中，是否有人知道或面對這個問題，如果是的話，你可以分享一些關於如何解決問題的信息。

預先感謝您。

問候 蒙娜麗莎

Answer 1

聯盟確實不保證結果的排序。但是，您可以在訂購信息中添加並使用：

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