使用ORACLE / SQL根据单个表中的两个条件创建两个单独的列

Question

I have a table like

A1 A2 A3 A4 A5 A6 
1  1   1  1  1  1
2  2   2  2  2  2
3  3   3  3  3  3

and I want do the task like:

SELECT A2 AS B2 WHERE A1 = 1
SELECT A2 AS B3 WHERE A1 = 2

How should I do this?

Answer 1

I think you can use a query like this:

SELECT 
    CASE WHEN A1 = 1 THEN A2 END As B2,
    CASE WHEN A1 = 2 THEN A2 END As B3,
FROM
    yourTable;

Note that B2 is as same as A2 if A1 = 1 else is null and so on.

Answer 2

SELECT 
    CASE WHEN A1 = 1 THEN A2 END As B2,
    CASE WHEN A1 = 2 THEN A2 END As B3
FROM TABLE_NAME
WHERE  A1 = 1 OR A1 = 2