Question

我很好奇是否可以使用我在select子句中为其他字段创建的列。

例如，我有这个查询 -

SELECT 
    users.officeid,
    COUNT(DISTINCT CASE WHEN users.active = 1 THEN user.id ELSE NULL END) as active_users,
    COUNT(CASE WHEN users.total = 1  THEN 1 ELSE NULL END) as total_users,
    active_users / total_users

FROM users  
GROUP BY 1

我想要另一列是active_users / total_users，但是我收到了错误 - ＆gt;

列＆＃34; active_users＆＃34;在用户中不存在

我是否需要将它们放在公用表表达式中然后从中进行选择？还有其他解决方案吗？谢谢！

Answer 1

with cccik as( SELECT 
    users.officeid,
    COUNT(DISTINCT CASE WHEN users.active = 1 THEN user.id ELSE NULL END) as active_users,
    COUNT(CASE WHEN users.total = 1  THEN 1 ELSE NULL END) as total_users,


FROM users  
GROUP BY 1)
select *, (active_users / total_users) from ccckik 
-- you can filter by officeid
-- where officeid = 5

Answer 2

“As ...”仅重命名查询输出的列。

如果您想在旅途中计算并避免创建其他列，您可以执行以下操作：

select count(column1), count(column1), 
count(column1) / count(column2)
from table

您还可以为其创建物化视图。

Answer 3

这个怎么样？

select officeid, active_users, total_users, active_users / total_users
from
(
SELECT 
    users.officeid,
    COUNT(DISTINCT CASE WHEN users.active = 1 THEN user.id ELSE NULL END) as active_users,
    COUNT(CASE WHEN users.total = 1  THEN 1 ELSE NULL END) as total_users
FROM users  
GROUP BY 1
)

如何使用我在select子句中创建的列？

3 个答案: