如何使用 SQL 查询对访问进行求和？

Question

我正在尝试过滤 SQL 数据库。

每行代表一个用户，我关注的主列标题为 last_visited，格式为… 2009-06-17 12:15:32。

过去一天/一周/一个月有多少用户访问过？

像：

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

Answer 1

那么是列文本还是日期时间？ 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，您可能会发现类似这样的有用信息：

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)

Answer 2

如何在iReport中使用SQL查询同一项目的多个SUM

SELECT
  SUM(case when (NOW()-1) <= datetime then 1 else 0 end) as 'today',
  SUM(case when (NOW()-7) <= datetime then 1 else 0 end) as 'thisweek',
  COUNT(*) as 'thismonth'
FROM
  table
WHERE
  (NOW()-30) <= datetime AND datetime <= NOW()