with data as (

select '2023-01-01' as dt ,'UserA' as user_name union all
select '2023-01-01' as dt ,'UserB' as user_name union all
select '2023-01-02' as dt ,'UserA' as user_name union all
select '2023-01-03' as dt ,'UserC' as user_name union all
select '2023-01-04' as dt ,'UserA' as user_name union all
select '2023-01-05' as dt ,'UserB' as user_name union all
select '2023-01-06' as dt ,'UserA' as user_name union all
select '2023-01-07' as dt ,'UserC' as user_name union all
select '2023-01-09' as dt ,'UserA' as user_name union all
select '2023-01-10' as dt ,'UserB' as user_name union all
select '2023-01-11' as dt ,'UserA' as user_name union all
select '2023-01-12' as dt ,'UserC' as user_name union all
select '2023-01-13' as dt ,'UserA' as user_name union all
select '2023-01-14' as dt ,'UserB' as user_name union all
select '2023-01-15' as dt ,'UserA' as user_name union all
select '2023-01-16' as dt ,'UserC' as user_name union all
select '2023-01-17' as dt ,'UserA' as user_name union all
select '2023-01-18' as dt ,'UserB' as user_name
)
select
t.dt,
date_add(t.dt, 7) dt_to,
count(distinct t.user_name) as cnt
from
(
select
d1.dt,
d2.user_name
from
data d1
join data d2
where
1 = 1
--and d1.dt > d2.dt
and datediff(d1.dt, d2.dt) <= 7
) t
group by
dt
----

大数据量不建议这样做

我这开锁 100，兄弟

买个发胶自己修修

快乐的童年

@rylei 不过是望山跑死马

扎辫子不就得了

技术大神也是靠时间钻研的，讲道理对于大多数精力有限的人来说到底学习本身是不会带来快乐的，回报才能。

如果是海外客服可是要上夜班的

语雀

@nutting 我大概心存侥幸

@shakoon 14 版本，好像已经有 15 ；其他的更加偏向数据库管理方面而 ide 方面，debug 好像没有，但是 plsql 写代码也没说好用到哪里去，我也算是用了很多年，自己调的算比较好用了，我见过有些老人用 plsqldeveloper11 这个经典版本，因为有些插件甚至都没有再更新了。每个版本都有一个问题，关闭的时候要卡挺久的。

同迪卡侬，有足球内裤内衣，相当保暖

其实你可以找乘务员要求换，不然真的躺不下去，各种奇怪的毛

喝酒不一定利于睡眠，看资本论可能有效一点

连城诀 神照经

根本不是会写 sql 的人写得出来的样子，sqlboy 如是说