使用union在select查询中添加别名行

Question

我有一张桌子student(name_std,age_std,address_std)。当我写查询

select * from Student

显示

name_std  age_std  address_std
Deepak     22        London
Anjali     16        Srilanka

我的要求是当我查询select * from Student时，它应该给我输出

name_std  age_std  address_std
**Name       Age       Address**   <<alias row>>
Deepak     22        London
Anjali     16        Srilanka

请建议我一些解决方案

Answer 1

尝试UNION，如下所示：

SELECT 'Name' as name_std,'Age' as age_std, 'Address' as address_std FROM dual
UNION
SELECT name_std,to_char(age_std),address_std FROM Student

Answer 2

我认为您可以对每列使用alias来实现所需的输出。

SELECT name_std as Name age_std as Age address_std  as Address
FROM Student

Answer 3

您必须取消*并使用列名和别名

SELECT name_Std "Name", age_std "Age", address_std "Address"
FROM   student

Answer 4

假设age_std为数字 -

SELECT 'Name'    name_std, 
       'Age'     age_std, 
       'Address' address_std 
FROM   dual 
UNION ALL 
SELECT name_std, 
       To_char(age_std), 
       address_std 
FROM   student;