SQL查询根据移动日期窗口有条件地求和

Question

我试图弄清楚我的用户的一些滑动窗口统计信息.我有一个包含用户的表,以及created_at和verified_at等列.对于每个月,我想知道有多少用户注册了(由created_at的date_trunc创建的一个简单组),然后是那些人,在我的滑动窗口中验证了多少(称为60天).

我想做一个SQL查询,给我一些像:

Month    | Registered | Verified in 60 days
Jan 2009 | 1543       | 107
Feb 2009 | 2000       | 250

我正在使用postgresql.我开始看sum(case ...),但我不知道我是否可以让我的情况以某种方式依赖于date_trunc.

当然,这不起作用,但这里的想法是:

SELECT DATE_TRUNC('month', created_at) as month, 
COUNT(*) as registered,
SUM(CASE WHEN verified_at < month+60 THEN 1 ELSE 0 END) as verified
FROM users
GROUP BY DATE_TRUNC('month', created_at)

Answer 1

SELECT  COUNT(created_at) AS registered,
        SUM(CASE WHEN verified_at <= created_at + '60 day'::INTERVAL THEN 1 ELSE 0 END) AS verified
FROM    generate_series(1, 20) s
LEFT JOIN
        users
ON      created_at >= '2009-01-01'::datetime + (s || ' month')::interval
        AND created_at < '2009-01-01'::datetime + (s + 1 || ' month')::interval
GROUP BY
        s