SQL Server聚合函数查询

Question

我有一个名为MusicTrack的表格，包含MusicTrackID、TrackName和Duration三列。

我正在使用以下查询语句：

    Select Cast(DateAdd( ms,SUM(DateDiff( ms, '00:00:00', Duration)), '00:00:00' ) as time) 
as 'Total duration' from   
    MusicTrack  where MusicTrackID = '1' or MusicTrackID = '3'

这个查询将选定的两个音乐曲目的持续时间相加，并在一个名为“总持续时间”的临时列中显示。 “Duration”是Time数据类型，因此我将其转换为整数，然后再转回去。

我的问题是：我如何改变查询方式，以便还包括TrackName字段和持续时间的累计总和？或者包括临时列以及TrackName列。

这样显示就会有TrackName和Total duration... 大致如下：

TrackName   Duration   Total duration

Name1       00:03:00     00:03:00
Name2       00:03:01     00:06:01

我尝试仅将TrackName列包含在查询中，像这样：但它不起作用：

Select TrackName, Cast(....) From MusicTrack  where MusicTrackID = '1' or MusicTrackID = '3'

- user3103672

---

在SQL中研究“累计总数”。 - Yuriy Galanter

Answer 1

请尝试以下操作：

我创建了一个示例表格

SELECT * INTO TMPTIME 
 FROM (
SELECT 1 AS ID ,'Name1' AS NAME,'00:03:00' AS T    
UNION 
SELECT 2 AS ID,'Name2' AS NAME,'00:03:01' AS T    
UNION
SELECT  3 AS ID,'Name3' AS NAME,'00:03:02' AS T   
UNION
SELECT 4 AS ID,'Name4' AS NAME,'00:03:41' AS T    
)TMP

输出查询

SELECT ID,NAME, T AS TIME,
(SELECT 
cast(DATEADD(ms, SUM(DATEDIFF(ms, '00:00:00.000', cast (t as time) )), '00:00:00.000') as time)
FROM TMPTIME T1 WHERE T1.ID<=TMPTIME.ID
) AS TOTAL

 FROM TMPTIME

结果

ID  NAME    TIME    TOTAL
1   Name1   00:03:00    00:03:00.0000000
2   Name2   00:03:01    00:06:01.0000000
3   Name3   00:03:02    00:09:03.0000000
4   Name4   00:03:41    00:12:44.0000000

- sumit

Answer 2

sqlFiddle 适用于 SQL Server（而非 mySQL）

SELECT TrackName, Duration, Cast(DateAdd(ms,RunningTotal,'00:00:00') as time) as 'Total Duration'
FROM
(SELECT TrackName, Duration,
  SUM(DateDiff(ms,'00:00:00',Duration)) OVER(ORDER BY MusicTrackId 
     ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) 
      AS RunningTotal
  FROM MusicTrack
  WHERE MusicTrackId IN (1,3)
)T

这里找到语法 running total

对于mySql sqlFiddle，（不是SQL Server）

SELECT TrackName,Date_Format(Duration,'%k:%i:%s') as Duration,
                 Date_Format(runningTotal,'%k:%i:%s') as 'Total Duration'
FROM
  (SELECT TrackName, Duration,
          Sec_To_Time(@total:=@total + Time_To_Sec(Duration)) as runningTotal
   FROM MusicTrack,(SELECT @total:='00:00:00')T
   WHERE MusicTrackId IN (1,3)
   ORDER BY MusicTrackId
  )Result

- Tin Tran