Question

我试图按字母顺序按值对每一列进行排序，然后再按NULL 。但是，它不起作用。我试图在完全加入之前在每个查询中按顺序排列，但是这不允许这样做，那么达到目标的可能方法有哪些？

Select t1.Name AS Doctor, t2.Name AS Professor, t3.Name AS Singer,t4.Name AS Actor
FROM (
      SELECT Name 
      FROM Occupation
      Where Occupation ='Doctor' 
                                )  t1 
FULL JOIN
    (
     SELECT Name 
     FROM Occupation
     Where Occupation ='Professor'
                                ) t2
on t1.Name=t2.Name
FULL JOIN
  (
     SELECT Name 
     FROM Occupation
     Where Occupation ='Singer'
                                ) t3
on t1.Name=t3.Name
FULL JOIN
   (
     SELECT Name 
     FROM Occupation
     Where Occupation ='Actor'
                               ) t4
on t1.Name=t4.Name
ORDER BY Doctor ASC, Professor ASC, Singer ASC, Actor ASC

错误的结果：

Doctor    Professor    Singer  Actor
-------------------------------------------
  NULL     NULL         NULL    Jane
  NULL     NULL         NULL    Julia
  NULL     NULL         NULL    Maria
  NULL     NULL         Meera   NULL
  NULL     NULL         Priya   NULL
  NULL     Ashley       NULL    NULL
  NULL     Christeen    NULL    NULL
  NULL     Ketty        NULL    NULL
  Jenny    NULL         NULL    NULL
  Samantha NULL         NULL    NULL

预期结果：

Doctor    Professor    Singer  Actor
-------------------------------------------
  Jenny    Ashley       Meera   Jane
  Samantha Christeen    Priya   Julia
  NULL     Ketty        NULL    Maria
  NULL     NULL         NULL    NULL
  NULL     NULL         NULL    NULL
  NULL     NULL         NULL    NULL
  NULL     NULL         NULL    NULL
  NULL     NULL         NULL    NULL
  NULL     NULL         NULL    NULL
  NULL     NULL         NULL    NULL

Answer 1

使用CASE，如果该值为空，则返回的值要大于不为空的值。

...
ORDER BY CASE
           WHEN doctor IS NULL THEN
             1
           ELSE
             0
         END,
         doctor,
         CASE
           WHEN professor IS NULL THEN
             1
           ELSE
             0
         END,
         professor,
         CASE
           WHEN singer IS NULL THEN
             1
           ELSE
             0
         END,
         singer,
         CASE
           WHEN actor IS NULL THEN
             1
           ELSE
             0
         END,
         actor

Answer 2

您可以使用

ORDER BY isnull(Doctor, 'zzzzzzzzzzzzzzz') ASC
       , isnull(Professor, 'zzzzzzzzzzzzzzz') ASC
       , isnull(Singer, 'zzzzzzzzzzzzzzz') ASC
       , isnull(Actor, 'zzzzzzzzzzzzzzz') ASC

Answer 3

您也可以尝试

order by case when Column is not null then Column else Replicate(char(255),Len(255)) end

您用列的精确长度替换 Len（255）中的255。

我认为这是最可靠的解决方案，因为如果数据库值'z'中的所有ascii字符均为122，则用户可能会使用例如。 '（'，这会弄乱您的排序。

但是如果您没有这种极端的情况，Milad Aghamohammadi的anwser也可以，而且简单得多

在NULL SQLSERVER之前按值排序

3 个答案: