如何使用SQL查询总结访问次数？

Question

我正在尝试过滤SQL数据库.

每行代表一个用户,我关注的主要栏目标题为last_visited,格式为... 2009-06-17 12:15:32.

有多少用户在最后一天/周/月访问过？

像:

SELECT COUNT(*) AS USERS_TODAY
FROM parts_users
Where updated_at > (NOW()-7)

Answer 1

列文本或日期时间也是如此？如果是前者:

SELECT COUNT(*) AS USERS_TODAY 
FROM parts_users
WHERE CONVERT(datetime, updated_at, 120) > DATEADD(day, -7, GETDATE())

如果是后者,则省略CONVERT.

或者,你可能会发现这样的东西很有用:

SELECT CONVERT(datetime, LEFT(updated_at, 10), 120) AS DATE_ONLY,
       COUNT(*) AS USERS_TODAY 
FROM parts_users
WHERE CONVERT(datetime, updated_at, 120) > DATEADD(day, -7, GETDATE())
GROUP BY CONVERT(datetime, LEFT(updated_at, 10), 120)