sql - 如何在teradata中按级别转换连接

Question

我试图将oracle的按级别连接功能转换为teradata。我在网上看过很多例子，但这个特别的例子不同，

 (SELECT 
     CASE LEVEL 
        WHEN 1 THEN 'MB'
        WHEN 2 THEN 'SB'
        ELSE 'TOTAL'
     END AS DRUG_SOURCE
 FROM
    DUAL 
 CONNECT BY LEVEL <= 3) RW  

如果你们有任何想法，请告诉我。

Answer 1

嘿，我找到了解决方案。抱歉，我无法清楚地解释我的问题。

下面的代码将完全按照我在 teradata 中想要的方式工作

select 'MB' as DRUG_SOURCE from dual  
union  
select 'SB' as DRUG_SOURCE from dual  
Union  
select 'TOTAL' as DRUG_SOURCE from dual  

Answer 2

你可以试试这段代码：

select DRUG_SOURCE from (select 'MB' as DRUG_SOURCE,1 as id) a
union all
select DRUG_SOURCE from (select 'SB' as DRUG_SOURCE,2 as id) b
union all
select DRUG_SOURCE from (select 'TOTAL' as DRUG_SOURCE,3 as id) c