使用工會

Question

添加別名行中選擇查詢我有一個表student(name_std,age_std,address_std)。當我寫查詢

select * from Student 

它顯示

name_std age_std address_std 
Deepak  22  London 
Anjali  16  Srilanka 

我的要求是，當我查詢select * from Student，它應該給我輸出像

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

請建議我一些解決方案

Answer 1

嘗試UNION象下面這樣：

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

我想你可以使用alias來實現你的每一列期望的輸出。

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

Answer 3

您將有*做掉，並使用列名和別名

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

Answer 4

假設age_std爲數字 -

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;