Question

我有2个表，一个包含任务的表和一个表＆＃34; Tasklog＆＃34;存储任务进度的地方

Tasks
ID Description 
1  task1
2  task2
3  task3
4  task4
5  task5

任务日志

ID taskId dtTime        Status
1   1       2016-01-01  new
2   1       2016-02-10  in progress
3   1       2016-03-03  closed
4   2       2016-01-01  new
5   2       2016-01-10  in progress
6   2       2016-01-11  closed
7   3       2016-01-01  new 
8   4       2016-01-01  new
9   5       2016-01-01  new
10  5       2016-01-01  in progress

一个任务可以有多个任务日志记录现在我想创建一个报告来显示有多少任务在哪里打开＆＃34;每月（开放意味着他们在过去24个月内没有状态＆＃34;关闭＆＃34;在那个月内）没有任务日志记录。

所以我需要这样的东西：

2016-01 4
2016-02 4
2016-03 3

我认为这些应该是查询应该产生的实际数字。

我很难写出正确的查询来做到这一点。我想我已经接近了，但是通过下面的查询我计算任务日志记录，而不管他们有多少任务日志记录，我想计算任务记录。

select month(dtTime) month, year(dtTime) year, count(t.id) as number
    from tasklog tl
    join tasks t on t.id = taskId
    where dtTime > DATE_ADD(now(), INTERVAL -2 YEAR)
    and t.id not in ( 
        select id from tasklog tl1 
        where status in ('closed')
        and month(tl1.dtTime) = month(tl.dtTime) 
        and year(tl1.dtTime) = year(tl.dtTime)
    )
    group by month(dtTime), year(dtTime)
    order by dtTime;

有什么建议我最好能做到这一点吗？

创建/填充表格的代码：

CREATE TABLE tasks
    (`id` int, `description` varchar(5))
;

INSERT INTO tasks
    (`id`, `description`)
VALUES
    (1, 'task1'),
    (2, 'task2'),
    (3, 'task3'),
    (4, 'task4'),
    (5, 'task5')
;


CREATE TABLE tasklog
    (`ID` int, `taskId` int, `dtTime` datetime, `Status` varchar(11))
;

INSERT INTO tasklog
    (`ID`, `taskId`, `dtTime`, `Status`)
VALUES
    (1, 1, '2016-01-01 00:00:00', 'new'),
    (2, 1, '2016-02-10 00:00:00', 'in progress'),
    (3, 1, '2016-03-03 00:00:00', 'closed'),
    (4, 2, '2016-01-01 00:00:00', 'new'),
    (5, 2, '2016-01-10 00:00:00', 'in progress'),
    (6, 2, '2016-01-11 00:00:00', 'closed'),
    (7, 3, '2016-01-01 00:00:00', 'new'),
    (8, 4, '2016-01-01 00:00:00', 'new'),
    (9, 5, '2016-01-01 00:00:00', 'new'),
    (10, 5, '2016-01-01 00:00:00', 'in progress')
;

响应Stefano Zanini的更新

似乎两种解决方案都没有给我正确的结果。我相信正确的结果是：

2016-01 4
2016-02 4
2016-03 3

你的查询只给了我：

1   2016    4

如果我将distinct添加到我的查询中，我会得到：

1   2016    5
2   2016    1
3   2016    1

Answer 1

我会选择左联盟

select month(tl.dtTime) month, year(tl.dtTime) year, count(t.id) as number
    from tasks t
    join tasklog tl
    on t.id = tl.taskId and tl.status = 'new'
    left join tasklog tl2
    on t.id = tl2.taskId and month(tl.dtTime) = month(tl2.dtTime) and tl2.status = 'closed'
    where dtTime > DATE_ADD(now(), INTERVAL -2 YEAR)
    and tl2.taskId is null
    group by month(tl.dtTime), year(tl.dtTime)
    order by dtTime;

修改

...但您可能只需要在distinct
中添加count条款
count(distinct t.id)

进一步解释后编辑

我误解了这个要求。这样就可以了：

select distinct mm.month, count(distinct tl.taskId) from (select distinct month(dtTime) mm from tasklog) mm join tasklog tl on mm.montId >= month(tl.dtTime) and tl.Status = 'new' left join tasklog tl2 on mm.month >= month(tl2.dtTime) and tl2.Status = 'closed' and tl.taskId = tl2.taskId where tl2.taskId is null group by mm.month order by 1;

第一个加入每个月加入到该月开放的所有任务。对于第二个连接，左边的连接，如果任务在该月或之前的任务中关闭，则为每个月/ taskId提供一个值。从这里，您只能过滤每月的打开任务，过滤没有此值的行。

您必须添加年份并可能优化连接子句，但使用您提供的示例数据，此查询完全没问题。

Answer 2

这就是我最终的结果：

select  distinct mm.year as year, 
                 mm.month as month, 
                 count(distinct tl.taskId) number
from    (select distinct month(dtTime) month , year(dttime) year  from tasklog) mm
join    tasklog tl
 on     mm.month >= month(tl.dtTime) and mm.year >= year(tl.dtTime) and tl.Status !='closed'
left join
        tasklog tl2
 on     mm.month >= month(tl2.dtTime) and mm.year >= year(tl2.dtTime) and tl2.Status = 'closed' and tl.taskId = tl2.taskId
where   tl2.taskId is null
group by mm.month
order by 1;

mysql：计算子表中的记录，按日期分组

2 个答案: