我需要帮助在MySQL 5.0.77中制作一个查询，根据下面显示的数据（在办公室中进行一天的通话），返回并发电话的峰值数量。我只是想知道在一天中的任何时间同时通电话的人数最多。
首先，这是MySQL表：
CREATE TABLE `call_log` (
`call_id` int(11) NOT NULL auto_increment,
`call_datetime` datetime default NULL,
`call_length` time default NULL,
PRIMARY KEY (`call_id`)
)
我使用以下命令将数据加载到表中：
LOAD DATA LOCAL INFILE 'call_log_import.csv' INTO TABLE call_log FIELDS TERMINATED BY ',' LINE TERMINATED BY '\n' (call_datetime, call_length);
以下是CSV格式的实际行数据：
2012-11-07 5:28:00,0:00:20
2012-11-07 7:04:00,0:00:20
2012-11-07 7:04:00,0:00:30
2012-11-07 7:04:00,0:00:30
2012-11-07 7:25:00,0:00:34
2012-11-07 7:25:00,0:00:37
2012-11-07 7:25:00,0:00:38
2012-11-07 7:30:00,0:00:16
2012-11-07 7:49:00,0:01:29
2012-11-07 7:55:00,0:00:43
2012-11-07 7:55:00,0:00:46
2012-11-07 7:55:00,0:00:46
2012-11-07 8:00:00,0:25:01
2012-11-07 8:00:00,0:00:35
2012-11-07 8:01:00,0:00:35
2012-11-07 8:01:00,0:00:35
2012-11-07 8:02:00,0:00:36
2012-11-07 8:02:00,0:03:03
2012-11-07 8:07:00,0:00:07
2012-11-07 8:08:00,0:00:08
2012-11-07 8:12:00,0:00:34
2012-11-07 8:12:00,0:00:44
2012-11-07 8:18:00,0:01:05
2012-11-07 8:28:00,0:01:05
2012-11-07 8:29:00,0:00:18
2012-11-07 8:31:00,0:00:05
2012-11-07 8:31:00,0:00:00
2012-11-07 8:31:00,0:00:11
2012-11-07 8:32:00,0:00:01
2012-11-07 8:32:00,0:27:26
2012-11-07 8:32:00,0:00:00
2012-11-07 8:32:00,0:00:00
2012-11-07 8:32:00,0:00:00
2012-11-07 8:32:00,0:00:38
2012-11-07 8:33:00,0:00:35
2012-11-07 8:33:00,0:00:04
2012-11-07 8:34:00,0:01:10
2012-11-07 8:35:00,0:09:44
2012-11-07 8:35:00,0:22:21
2012-11-07 8:35:00,0:00:17
2012-11-07 8:35:00,0:21:42
2012-11-07 8:35:00,0:21:46
2012-11-07 8:35:00,0:21:46
2012-11-07 8:37:00,0:00:29
2012-11-07 8:38:00,0:00:29
2012-11-07 8:39:00,0:06:50
2012-11-07 8:39:00,0:08:23
2012-11-07 8:53:00,0:05:01
2012-11-07 8:53:00,0:05:05
2012-11-07 8:53:00,0:05:05
2012-11-07 8:57:00,0:01:04
2012-11-07 9:00:00,0:29:40
2012-11-07 9:01:00,0:00:20
2012-11-07 9:01:00,0:01:27
2012-11-07 9:02:00,0:27:00
2012-11-07 9:03:00,0:26:18
2012-11-07 9:03:00,0:00:18
2012-11-07 9:09:00,0:01:16
2012-11-07 9:12:00,0:02:53
2012-11-07 9:12:00,0:01:09
2012-11-07 9:12:00,0:27:27
2012-11-07 9:14:00,0:07:13
2012-11-07 9:14:00,0:07:18
2012-11-07 9:14:00,0:07:18
2012-11-07 9:18:00,0:11:39
2012-11-07 9:18:00,0:11:55
2012-11-07 9:18:00,0:00:16
2012-11-07 9:17:00,0:12:15
2012-11-07 9:18:00,0:00:48
2012-11-07 9:18:00,0:00:52
2012-11-07 9:18:00,0:00:52
2012-11-07 9:19:00,0:01:12
2012-11-07 9:21:00,0:00:03
2012-11-07 9:22:00,0:02:41
2012-11-07 9:22:00,0:02:36
2012-11-07 9:22:00,0:02:49
2012-11-07 9:24:00,0:01:34
2012-11-07 9:25:00,0:06:10
2012-11-07 9:25:00,0:06:14
2012-11-07 9:25:00,0:06:14
2012-11-07 9:31:00,0:00:43
2012-11-07 9:33:00,0:00:03
2012-11-07 9:33:00,0:00:03
2012-11-07 9:33:00,0:00:03
2012-11-07 9:33:00,0:00:03
2012-11-07 9:33:00,0:00:03
2012-11-07 9:33:00,0:05:57
2012-11-07 9:32:00,0:00:30
2012-11-07 9:32:00,0:00:30
2012-11-07 9:32:00,0:06:28
2012-11-07 9:32:00,0:06:53
2012-11-07 9:32:00,0:00:35
2012-11-07 9:32:00,0:00:20
2012-11-07 9:32:00,0:01:04
2012-11-07 9:32:00,0:01:04
2012-11-07 9:32:00,0:00:41
2012-11-07 9:36:00,0:00:27
2012-11-07 9:37:00,0:23:53
2012-11-07 9:38:00,0:01:51
2012-11-07 9:40:00,0:06:40
2012-11-07 9:40:00,0:06:44
2012-11-07 9:40:00,0:06:44
2012-11-07 9:44:00,0:01:19
2012-11-07 9:46:00,0:00:55
2012-11-07 9:46:00,0:02:01
2012-11-07 9:47:00,0:20:00
2012-11-07 9:47:00,0:02:22
2012-11-07 9:47:00,0:07:12
2012-11-07 9:47:00,0:02:22
2012-11-07 9:47:00,0:00:13
2012-11-07 9:48:00,0:00:41
2012-11-07 9:48:00,0:01:25
2012-11-07 9:50:00,0:01:24
2012-11-07 9:52:00,0:00:06
2012-11-07 9:54:00,0:00:06
2012-11-07 9:57:00,0:00:28
2012-11-07 9:57:00,0:00:20
2012-11-07 9:57:00,0:00:48
2012-11-07 9:58:00,0:00:06
2012-11-07 9:58:00,0:00:06
2012-11-07 9:58:00,0:00:06
2012-11-07 9:58:00,0:00:06
2012-11-07 9:58:00,0:00:06
2012-11-07 9:58:00,0:06:49
2012-11-07 9:58:00,0:07:19
2012-11-07 9:58:00,0:00:30
2012-11-07 9:58:00,0:00:30
2012-11-07 9:58:00,0:07:38
2012-11-07 9:58:00,0:01:36
2012-11-07 9:59:00,0:00:59
2012-11-07 9:59:00,0:01:00
2012-11-07 10:00:00,0:17:43
2012-11-07 10:00:00,0:00:21
2012-11-07 10:00:00,1:02:29
2012-11-07 10:01:00,0:00:03
2012-11-07 10:01:00,0:00:03
2012-11-07 10:01:00,0:00:52
2012-11-07 10:01:00,0:20:23
2012-11-07 10:01:00,0:01:09
2012-11-07 10:01:00,0:00:20
2012-11-07 10:01:00,0:01:15
2012-11-07 10:02:00,0:00:01
2012-11-07 10:02:00,0:00:36
2012-11-07 10:02:00,0:00:48
2012-11-07 10:02:00,0:21:49
2012-11-07 10:03:00,0:40:24
2012-11-07 10:04:00,0:00:02
2012-11-07 10:04:00,0:00:02
2012-11-07 10:04:00,0:00:02
2012-11-07 10:04:00,0:05:59
2012-11-07 10:04:00,0:00:02
2012-11-07 10:04:00,0:00:02
2012-11-07 10:04:00,0:05:59
2012-11-07 10:03:00,0:06:20
2012-11-07 10:03:00,0:00:22
2012-11-07 10:06:00,0:20:35
2012-11-07 10:07:00,0:02:44
2012-11-07 10:08:00,0:00:01
2012-11-07 10:09:00,0:00:29
2012-11-07 10:09:00,0:01:17
2012-11-07 10:10:00,0:00:02
2012-11-07 10:11:00,0:00:02
2012-11-07 10:12:00,0:01:43
2012-11-07 10:12:00,0:24:01
2012-11-07 10:12:00,0:24:04
2012-11-07 10:12:00,0:24:04
2012-11-07 10:12:00,0:01:23
2012-11-07 10:13:00,0:03:51
2012-11-07 10:13:00,0:03:40
2012-11-07 10:14:00,0:09:52
2012-11-07 10:16:00,0:13:33
2012-11-07 10:16:00,0:13:37
2012-11-07 10:16:00,0:13:37
2012-11-07 10:21:00,0:00:20
2012-11-07 10:21:00,0:01:18
2012-11-07 10:21:00,0:01:18
2012-11-07 10:22:00,0:00:21
2012-11-07 10:22:00,0:00:32
2012-11-07 10:22:00,0:00:32
2012-11-07 10:22:00,0:04:31
2012-11-07 10:22:00,0:00:57
2012-11-07 10:23:00,0:10:23
2012-11-07 10:24:00,0:01:20
2012-11-07 10:24:00,0:01:24
2012-11-07 10:24:00,0:01:24
2012-11-07 10:25:00,0:27:34
2012-11-07 10:28:00,0:00:49
2012-11-07 10:30:00,0:01:46
2012-11-07 10:30:00,0:01:51
2012-11-07 10:30:00,0:01:51
2012-11-07 10:30:00,0:01:01
2012-11-07 10:31:00,0:00:43
2012-11-07 10:31:00,0:15:08
2012-11-07 10:33:00,0:02:37
2012-11-07 10:35:00,0:00:21
2012-11-07 10:35:00,0:01:24
2012-11-07 10:35:00,0:01:24
2012-11-07 10:37:00,0:02:07
2012-11-07 10:37:00,0:00:08
2012-11-07 10:38:00,0:00:10
2012-11-07 10:39:00,0:01:37
2012-11-07 10:39:00,0:00:21
2012-11-07 10:39:00,0:01:53
2012-11-07 10:39:00,0:00:03
2012-11-07 10:40:00,0:00:34
2012-11-07 10:41:00,0:00:00
2012-11-07 10:41:00,0:00:00
2012-11-07 10:41:00,0:00:00
2012-11-07 10:41:00,0:02:20
2012-11-07 10:45:00,0:07:57
2012-11-07 10:51:00,0:00:20
2012-11-07 10:51:00,0:00:56
2012-11-07 10:50:00,0:01:12
2012-11-07 10:50:00,0:00:04
2012-11-07 10:50:00,0:00:04
2012-11-07 10:50:00,0:00:04
2012-11-07 10:50:00,0:00:04
2012-11-07 10:50:00,0:00:04
2012-11-07 10:50:00,0:01:44
2012-11-07 10:50:00,0:00:31
2012-11-07 10:50:00,0:00:31
2012-11-07 10:49:00,0:03:05
2012-11-07 10:54:00,0:00:20
2012-11-07 10:54:00,0:01:02
2012-11-07 10:54:00,0:01:02
2012-11-07 10:55:00,0:02:08
2012-11-07 10:56:00,0:00:33
2012-11-07 10:56:00,0:00:05
2012-11-07 10:59:00,0:24:33
2012-11-07 10:59:00,0:24:37
2012-11-07 10:59:00,0:24:37
2012-11-07 11:00:00,0:29:41
2012-11-07 11:00:00,0:07:38
2012-11-07 11:00:00,0:00:51
2012-11-07 11:01:00,0:00:33
2012-11-07 11:02:00,0:28:12
2012-11-07 11:02:00,0:35:02
2012-11-07 11:02:00,0:35:05
2012-11-07 11:02:00,0:35:05
2012-11-07 11:02:00,0:21:29
2012-11-07 11:03:00,0:02:24
2012-11-07 11:03:00,0:02:28
2012-11-07 11:03:00,0:02:28
2012-11-07 11:03:00,0:00:03
2012-11-07 11:04:00,0:34:28
2012-11-07 11:04:00,0:08:20
2012-11-07 11:04:00,0:01:01
2012-11-07 11:06:00,0:16:09
2012-11-07 11:08:00,0:00:50
2012-11-07 11:11:00,0:02:08
2012-11-07 11:14:00,0:01:22
2012-11-07 11:14:00,0:01:26
2012-11-07 11:14:00,0:01:26
2012-11-07 11:14:00,0:00:20
2012-11-07 11:14:00,0:00:57
2012-11-07 11:14:00,0:00:57
2012-11-07 11:15:00,0:09:48
2012-11-07 11:15:00,0:11:10
2012-11-07 11:16:00,0:00:55
2012-11-07 11:18:00,0:00:48
2012-11-07 11:22:00,0:00:51
2012-11-07 11:22:00,0:00:51
2012-11-07 11:22:00,0:00:51
2012-11-07 11:22:00,0:01:16
2012-11-07 11:28:00,0:03:36
2012-11-07 11:29:00,0:13:18
2012-11-07 11:30:00,0:03:47
2012-11-07 11:30:00,0:20:44
2012-11-07 11:30:00,0:01:29
2012-11-07 11:32:00,0:00:39
2012-11-07 11:32:00,0:07:04
2012-11-07 11:35:00,0:02:04
2012-11-07 11:35:00,0:00:20
2012-11-07 11:35:00,0:00:32
2012-11-07 11:35:00,0:00:32
2012-11-07 11:37:00,0:18:14
2012-11-07 11:37:00,0:18:14
2012-11-07 11:37:00,0:00:17
2012-11-07 11:37:00,0:00:18
2012-11-07 11:37:00,0:00:18
2012-11-07 11:36:00,0:18:57
2012-11-07 11:37:00,0:24:10
2012-11-07 11:38:00,0:00:19
2012-11-07 11:38:00,0:00:02
2012-11-07 11:38:00,0:00:02
2012-11-07 11:38:00,0:01:29
2012-11-07 11:41:00,0:00:02
2012-11-07 11:41:00,0:00:02
2012-11-07 11:41:00,0:00:02
2012-11-07 11:41:00,0:04:48
2012-11-07 11:41:00,0:00:02
2012-11-07 11:41:00,0:00:02
2012-11-07 11:41:00,0:04:48
2012-11-07 11:40:00,0:05:09
2012-11-07 11:41:00,0:01:41
2012-11-07 11:42:00,0:15:24
2012-11-07 11:42:00,0:15:30
2012-11-07 11:42:00,0:15:30
2012-11-07 11:59:00,0:00:20
2012-11-07 11:59:00,0:00:31
2012-11-07 11:59:00,0:00:31
2012-11-07 12:00:00,0:08:56
2012-11-07 12:01:00,0:22:31
2012-11-07 12:02:00,0:00:26
2012-11-07 12:02:00,0:33:20
2012-11-07 12:03:00,0:33:45
2012-11-07 12:06:00,0:00:56
2012-11-07 12:18:00,0:00:55
2012-11-07 12:18:00,0:00:55
2012-11-07 12:18:00,0:01:04
2012-11-07 12:24:00,0:00:02
2012-11-07 12:24:00,0:00:02
2012-11-07 12:24:00,0:00:25
2012-11-07 12:25:00,0:00:21
2012-11-07 12:25:00,0:01:08
2012-11-07 12:25:00,0:01:08
2012-11-07 12:26:00,0:00:20
2012-11-07 12:26:00,0:00:54
2012-11-07 12:26:00,0:00:54
2012-11-07 12:29:00,0:00:11
2012-11-07 12:31:00,0:02:10
2012-11-07 12:31:00,0:12:35
2012-11-07 12:31:00,0:06:26
2012-11-07 12:46:00,0:00:34
2012-11-07 12:47:00,0:01:01
2012-11-07 12:47:00,0:01:24
2012-11-07 12:48:00,0:00:15
2012-11-07 12:48:00,0:00:20
2012-11-07 12:48:00,0:00:20
2012-11-07 12:48:00,0:00:18
2012-11-07 12:50:00,0:00:20
2012-11-07 12:50:00,0:00:32
2012-11-07 12:50:00,0:00:32
2012-11-07 12:55:00,0:01:30
2012-11-07 12:55:00,0:01:31
2012-11-07 12:55:00,0:00:17
2012-11-07 12:55:00,0:00:17
2012-11-07 12:55:00,0:00:18
2012-11-07 12:54:00,0:02:13
2012-11-07 12:59:00,0:36:03
2012-11-07 13:00:00,0:09:42
2012-11-07 13:00:00,0:13:35
2012-11-07 13:01:00,0:18:08
2012-11-07 13:01:00,0:28:37
2012-11-07 13:02:00,0:01:26
2012-11-07 13:02:00,0:00:01
2012-11-07 13:02:00,0:09:42
2012-11-07 13:03:00,0:04:53
2012-11-07 13:04:00,0:00:35
2012-11-07 13:12:00,0:14:28
2012-11-07 13:12:00,0:14:28
2012-11-07 13:12:00,0:14:42
2012-11-07 13:13:00,0:00:45
2012-11-07 13:14:00,0:01:27
2012-11-07 13:15:00,0:13:04
2012-11-07 13:14:00,0:13:08
2012-11-07 13:14:00,0:13:08
2012-11-07 13:14:00,0:15:32
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2012-11-07 13:15:00,0:00:30
2012-11-07 13:16:00,0:00:42
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2012-11-07 13:24:00,0:00:05
2012-11-07 13:26:00,0:03:07
2012-11-07 13:27:00,0:00:41
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2012-11-07 13:42:00,0:06:55
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2012-11-07 13:45:00,0:00:33
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2012-11-07 13:51:00,0:01:55
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2012-11-07 14:06:00,0:00:34
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2012-11-07 14:15:00,0:01:53
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2012-11-07 14:19:00,0:11:31
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2012-11-07 14:21:00,0:00:00
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答案 0 :(得分：3)
对于日志中的每个呼叫，计算在该call_datetime处于活动状态的呼叫，然后找到最大值：
SELECT MAX(calls) FROM
(SELECT cl1.call_datetime, COUNT(*) AS calls
FROM call_log cl1
INNER JOIN call_log cl2
ON cl1.call_datetime
BETWEEN cl2.call_datetime AND ADDTIME(cl2.call_datetime, cl2.call_length)
GROUP BY cl1.call_id) AS counts;
答案 1 :(得分：1)
Demo不包含您的所有数据（因为超过8000个字符，因此不允许在sqlfiddle上使用）但是一些示例数据
显示并发呼叫的最大数量
SELECT MAX(cnt) FROM
(SELECT cl1.b, COUNT(*) AS cnt
FROM calls cl1
INNER JOIN calls cl2
ON cl1.b
BETWEEN cl2.b AND ADDTIME(cl2.b, cl2.c)
GROUP BY cl1.a) AS counts;
以及所有可能的计数。
SELECT cnt FROM
(SELECT cl1.b, COUNT(*) AS cnt
FROM calls cl1
INNER JOIN calls cl2
ON cl1.b
BETWEEN cl2.b AND ADDTIME(cl2.b, cl2.c)
GROUP BY cl1.a) AS counts;
答案 2 :(得分：0)
select * from
(
select count(*), time(call_datetime) t0 from call_log
group by time(call_datetime)
) as q0 order by q0.t0 desc;
将group by更改为使用date, time, hour, min, sec等
答案 3 :(得分：0)
尝试为每个调用开始添加+1，为每个结尾添加-1，然后获取该+ 1 / -1列的累积总和
***如果需要，转换calldate或使用您的格式：
set @from:='2015-02-01';
set @to:='2015-03-01';
set @csum:=0;
SELECT DT,CallCount, (@csum := @csum + CallCount) as cumulative_sum
FROM
(select calldate AS DT, 1 AS CallCount
from cdr
where calldate between @from and @to
union all
select ADDDATE(calldate,INTERVAL duration SECOND) AS DT, -1 AS CallCount
from cdr
where calldate between @from and @to
) Calls
ORDER BY 1 asc;
我给了一个答案here