SQL集团通过定时

Question

我有有，我想组一个列的表，但只有最后一个系列的它（该表有一个时间戳列一起工作）例如表

Type | Time 
============= 
A | 1:00 
A | 1:05 
B | 1:10 
C | 1:15 
A | 1:20 
A | 1:25 
A | 1:30 

我想这些组做函数（SUM（），MAX（），AVG（））他们只获得小组就被打破之前，因此通过选择一个标准组将无法正常工作。

我想是这样的：

Type | count_in_series | MinTime 
================================ 
A | 2    | 1:00 
B | 1    | 1:10 
C | 1    | 1:15 
A | 3    | 1:20 

因为谁也不知道当发生变化的方式，给出的数据只是一个样本，以说明这一点。

这可能吗？

解决方案

我用这从下面的答案概念。原来我正在使用的程序不允许使用变量或WITH CTE。下面是一个使用子查询我的解决方案：

SELECT 
    Type 
    , max(t_stamp) as maxTime 
    , min(t_stamp) as minTime 
FROM 
    (SELECT 
     * 
     , ROW_NUMBER() OVER (ORDER BY t_stamp desc) - ROW_NUMBER() OVER (PARTITION BY Type ORDER BY t_stamp desc) as grouping 
    FROM MyTable) as t1 
GROUP BY t1.grouping, t1.Type 
ORDER BY min(t_stamp) desc 

Answer 1

如果你没有LAG，你可以只使用ROW_NUMBER()

SQL DEMO

With CTE AS (
    SELECT T.*,   
      ROW_NUMBER() OVER (ORDER BY [TIME]) as ID, 
      ROW_NUMBER() OVER (PARTITION BY [Type] ORDER BY [TIME]) as rn 
    FROM Table1 T  
) 
SELECT [Type], COUNT(*) Count , MIN(Time) Time 
FROM CTE 
GROUP BY [Type], ID - rn 
ORDER BY MIN(Time) 

输出

Answer 2

像这样的东西应该工作：-------
Check this SQL fiddle

SELECT 
    Type, 
    count('Type'), 
    min('Time') 
FROM table 
GROUP BY Type 

-----编辑如果你能使用用户变量，即工作：

SET @typeIndex = 1; 

SELECT 
    min(type) as type, 
    count(type) as count, 
    min(TIME_FORMAT(time, '%H %i')) as minTime 
FROM(
    SELECT 
    t.type, 
    t.time, 
    (SELECT type FROM timeTest tt 
     WHERE tt.time < t.time 
     ORDER BY time DESC LIMIT 1) as next_type, 
    IF(type != (SELECT type FROM timeTest tt 
     WHERE tt.time < t.time 
     ORDER BY time DESC LIMIT 1), @typeIndex := @typeIndex+1, "") as t , 
    @typeIndex as tipeIndex 
    FROM 
    timeTest t 
) temp 
GROUP BY temp.tipeIndex 

Answer 3

您可以使用lag和row_number获得正确的桶，然后做组p通过如下：

;with cte as (
select *, Bucket = sum(sm) over (order by RowN) from (
select *,sm = case when (lag(type,1) over (order by [time]) <> [type]) then 1 else 0 end, 
    RowN= row_number() over(order by [time]) from #yourtime 
    ) a 
    ) 
    select min([Type]) as [Type], count([Type]) as Count_in_Series, min([time]) as MinTime from cte 
    group by Bucket 

你的输出：

+------+-----------------+------------------+ 
| Type | Count_in_Series |  MinTime  | 
+------+-----------------+------------------+ 
| A |    2 | 01:00:00.0000000 | 
| B |    1 | 01:10:00.0000000 | 
| C |    1 | 01:15:00.0000000 | 
| A |    3 | 01:20:00.0000000 | 
+------+-----------------+------------------+ 

您的输入表：

create table #yourtime (type varchar(2), [Time] time) 

insert into #yourtime ([type], [time]) values 
('A','1:00') 
,('A','1:05') 
,('B','1:10') 
,('C','1:15') 
,('A','1:20') 
,('A','1:25') 
,('A','1:30')