sql - Oracle 按降序排列，最后为 NULL

Question

我的目标是按“降序”顺序打印查询结果。但问题是，具有 NULL 值的行位于列表的顶部。如果顺序是降序，如何将空行放在底部？

select mysubcat.subcat
       , mysubcat.subcatid as subcat_id
       , (select SUM(myad.PAGEVIEW) 
           from myad 
            where MYAD.CREATEDDATE between  '01-JUL-13 02.00.49.000000000 PM' and '13-JUL-13 02.00.49.000000000 PM'
            AND MYAD.status = 1 
            and  MYAD.mobileapp IS NULL
            and myad.subcatid = mysubcat.subcatid )as web_views 
from mysubcat 
order by web_views desc;

示例结果如下

                             SUBCAT_ID    WEB_VIEWS
Swimming Lessons                56        (null)    
Medical Services                17        (null)
Mobile Phones & Tablets         39        6519
Home Furnishing & Renovation   109        4519

顺序是降序排列的，我只想把空值的行放在打印结果的底部，怎么办？

Answer 1

您可以使用DESC NULLS LAST来实现这一点。

这是official documentation来自甲骨文。

NULLS LAST

Specifies that NULL values should be returned after non-NULL values.