如何计算不同的记录

问题描述

有人可以在SQL命令上为我提供帮助吗?

Could anybody please help me on SQL command?

我有一个表(tbl_sActivity)，其中包含以下数据:

I have a table (tbl_sActivity) that have below data:

输出应该是

我从网上搜索后得知，MS ACCESS无法使用COUNT(DISTINCT)函数.所以我在这个阶段停留了几天.

I've searched from net and learnt that MS ACCESS cannot use COUNT(DISTINCT) function. So I'm stuck at this stage for days.

推荐答案

尝试一下. 技巧"是首先有一个子查询，以获取用户ID和客户端ID的所有不同组合，然后对每个用户进行分组:

Try this one. The "trick" is to have a subquery first to get all the distinct combinations of user and client IDs and then do the grouping per user:

SELECT
    user_id
  , COUNT(*) AS count_distinct_clients
FROM
    ( SELECT DISTINCT
          user_id, 
          client_id
      FROM tbl_sActivity
    ) AS tmp
GROUP BY
    user_id ;

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