MYSQL:在单个语句中选择多个 if(field ='x' max(time)/if(field ='y' min(time)) 值

Question

我正在尝试让下面的选择语句起作用。本质上，我试图为每个代理和日期获取一行，其中包含代理状态 = '登录' 的最小(时间)，代理状态 = '注销' 的最大(时间)，timediff(最大( time),min(time)) 和 sum(duration) where agent-state = 'Ready'.

我当前的 SQL 语句对此并不完整，因为我一开始只是获取正确的最小/最大时间值并碰壁了。现在，返回的是登录的最短时间，而不是注销的最长时间。

AGENT, DATE,         TIME,      DURATION,   AGENT_STATE
Alex, 2013-01-01,   07:25:37,   00:00:00,   Logged-in
Alex, 2013-01-01,   07:26:01,   00:24:48,   Ready
Alex, 2013-01-01,   07:54:20,   00:21:47,   Ready
Alex, 2013-01-01,   08:28:11,   00:03:00,   Ready
Alex, 2013-01-01,   08:34:11,   00:06:29,   Ready
Alex, 2013-01-01,   08:44:30,   00:05:14,   Ready
Alex, 2013-01-01,   08:53:29,   00:06:52,   Ready
Alex, 2013-01-01,   09:03:48,   00:12:13,   Ready
Alex, 2013-01-01,   09:31:56,   00:36:44,   Ready
Alex, 2013-01-01,   09:32:27,   14:58:51,   Logout
Alex, 2013-01-01,   10:11:37,   00:00:00,   Logged-in
Alex, 2013-01-01,   10:12:26,   00:54:44,   Ready
Alex, 2013-01-01,   11:09:28,   00:47:48,   Ready
Alex, 2013-01-01,   11:57:33,   00:16:54,   Ready
Alex, 2013-01-01,   12:15:15,   00:17:32,   Ready
Alex, 2013-01-01,   12:34:44,   00:13:32,   Ready
Alex, 2013-01-01,   12:51:04,   00:16:44,   Ready
Alex, 2013-01-01,   13:12:36,   00:31:38,   Ready
Alex, 2013-01-01,   13:49:46,   00:39:14,   Ready
Alex, 2013-01-01,   14:31:42,   00:28:45,   Ready
Alex, 2013-01-01,   15:00:27,   14:58:51,   Logout

SQL语句:

select
 `agent`,
 `date`,
 if(`agent_state` = 'Logged-in', min(`time`), null) as `min_login`,
 if(`agent_state` = 'Logout', max(`time`),null) as `max_logout`
from
 t_cisco_agent_state_details
group by
 `agent`, `date`
order by
 `agent`, `date`, `time` asc;

感谢任何帮助或建议。

吉姆

Answer 1

你不能这样做。您在“其他”列中获得空值的原因是，当您按代理和日期分组时，agent_state 不存在。如果将 agent_state 添加到分组依据中，每个代理/日期将获得 3 行。这不是您想要的。

您需要一个子查询或几个自连接。尝试这样的事情:

SELECT agent,
       date,
       MIN(dur)                       AS total_duration,
       TIMEDIFF(MIN(maxt), MIN(mint)) AS time_difference_between_login_and_out,
       MIN(maxt)                      AS logout_time,
       MIN(mint)                      AS login_time
FROM   (SELECT agent,
               date,
               IF(agent_state = 'Ready', SUM(time), NULL)     AS dur,
               IF(agent_state = 'Logged-in', MIN(time), NULL) AS mint,
               IF(agent_state = 'Logout', MAX(time), NULL)    AS maxt,
               agent_state
        FROM   t_cisco_agent_state_details
        GROUP  BY agent,
                  date,
                  agent_state) AS subq
GROUP  BY agent,
          date 

子查询为每个代理状态、代理和日期创建一行。然后，您可以使用仅按代理人和日期分组的外部查询来提取您的时间。