Question

我需要在我的SQL语句中输出3个空列，我正在使用SQL开发人员Oracle 11g 例如：

SELECT
  c.CID, 
  c.CName,
  null, 
  null, 
  null, 
  r.RegionID, 
  r.RegionName
FROM
  Regions r 
  INNER JOIN Branch b ON b.RegionID = r.RegionID
  INNER JOIN Countries c ON c.CID = b.CID;

所以在SQL Developer的脚本输出/查询结果窗口中显示

  CID| CName | Null |   Null  | Null | RegionID  | RegionName
  ------------------------------
  C1 | ENG   | Null  | Null   | Null | R1        | UK   
  C2 | ...   | Null  | Null   | Null | R2        | ...
  C3 | ...   | Null  | Null   | Null | R3        | ...

如果我可以做类似的事情，那将是理想的：

Select
Country,
Region, 
Null as Continent,
Null as hemisphere

etc

我知道这可能听起来很疯狂，但它只是为了格式化目的，直到数据库更新。

编辑：谢谢你，没有意识到它是如此直接，唯一的问题是我的空列在脚本输出屏幕上是巨大的，即使它是空的，有没有办法使它更合理的大小？

Answer 1

嗯，你可以按照你提出的方式做到......：

SELECT
  c.CID, 
  c.CName,
  CAST(null AS VARCHAR2(1)) AS Continent, 
  null AS hemisphere, 
  null AS something, 
  r.RegionID, 
  r.RegionName
FROM
  Regions r 
  INNER JOIN Branch b ON b.RegionID = r.RegionID
  INNER JOIN Countries c ON c.CID = b.CID;

Answer 2

实际上，这应该有效。

SELECT
  c.CID, 
  c.CName,
  null AS country, 
  null AS Region, 
  null AS hemisphere, 
  r.RegionID, 
  r.RegionName
FROM
  Regions r 
  INNER JOIN Branch b ON b.RegionID = r.RegionID
  INNER JOIN Countries c ON c.CID = b.CID;
-- Or, if you don't have any tables yet:
SELECT
  NULL AS CID, 
  NULL AS CName,
  NULL AS country, 
  NULL AS Region, 
  NULL AS hemisphere, 
  NULL AS RegionID, 
  NULL AS RegionName
FROM dual;

Answer 3

我认为通过显示null你的意思是基本上它应该是空的并显示为null所以你可以使用下面的查询：

Select
Country,
Region, 
''  Continent,
''  hemisphere,
from 
regions r;

在SQL Developer中为脚本输出选择空列

3 个答案: