Question

（MySql引擎）我有一张桌子记录了工作人员和俱乐部成员之间的联系，称为“联系人”。我需要通过比较会员在整个时间段之前和之后记录的平均次数来了解最新联系是否对会员出席产生了积极影响。登录存储在登录表中。用户信息存储在users表中。

以下sql语句为每个俱乐部会员的每次登录（每天1次）提取一条线，用于在此期间至少有一个联系人的俱乐部会员。我坚持的是找到每个成员的maxcontactdate之前和之后的登录总数。

所以我希望生成的表包含在recid上分组的行，fk_staff_users_recid

“recid”，“maxcontactdate”，“fk_staff_users_recid”，“pre_maxcontactdate_login_count”，“post_maxcontactdate_login_count”

有人可以帮忙吗？

SELECT
  recid,
  maxcontactdate,
  fk_staff_users_recid,
  logtime
FROM
(
  /* Selects user id, with the staff that made the contact, and the max contact date for that member of staff */
  SELECT fk_users_recid,
          fk_staff_users_recid,
          MAX(contactdate) AS maxcontactdate
  FROM
    contacts
  WHERE
    contactdate BETWEEN '2013-07-20' AND '2013-08-20'
  GROUP BY fk_users_recid, fk_staff_users_recid
)contacts,
users

JOIN
(
  /* Selects all login dates between the dates specified */
  SELECT fk_users_recid,
         DATE(logins.logintime) AS logtime
  FROM
    logins
  WHERE
    logintime BETWEEN '2013-07-20' AND '2013-08-20'
  GROUP BY fk_users_recid, logtime
)logins
ON logins.fk_users_recid = users.recid 

/* Only pull the members who had contacts during the period */
WHERE
users.recid = contacts.fk_users_recid

Answer 1

您可以使用条件计数（计数语句中的CASE WHEN ..）

来执行此操作

SELECT  recid,
        maxcontactdate,
        fk_staff_users_recid,
        COUNT(CASE WHEN logins.logtime < contacts.maxcontactdate THEN 1 END) AS pre_maxcontactdate_login_count,
        COUNT(CASE WHEN logins.logtime >= contacts.maxcontactdate THEN 1 END) AS post_maxcontactdate_login_count,
        COUNT(*) AS Total_Logins
FROM    (   SELECT  fk_users_recid, fk_staff_users_recid, MAX(contactdate) AS maxcontactdate
            FROM    contacts
            WHERE   contactdate BETWEEN '2013-07-20' AND '2013-08-20'
            GROUP BY fk_users_recid, fk_staff_users_recid
        ) contacts
        INNER JOIN Users    
            ON users.recid = contacts.fk_users_recid 
        INNER JOIN
        (   SELECT  fk_users_recid, DATE(logins.logintime) AS logtime
            FROM    logins
            WHERE   logintime BETWEEN '2013-07-20' AND '2013-08-20'
            GROUP BY fk_users_recid, logtime
        ) logins
            ON logins.fk_users_recid = users.recid
GROUP BY recid, maxcontactdate, fk_staff_users_recid;

计算在另一个表中最大日期之前和之后出现的一个表中的记录

1 个答案: