Show average difference between two time fields as MM:SS in SQL

Question

I am using SQL Server 2008. I have several rows of start_time and end_time. I want to calculate the average difference between these two times in a MM:SS format.

start_time | end_time     
10:15:30   | 10:15:45     
10:45:00   | 10:47:30

Row 1 would be a difference of 00:15, and row 2 would be a difference of 02:30. The average of the entire dataset would be 01:23 (1 minute and 23 seconds).

The code I'm using looks like the following, but only returns an integer.

AVG(DATEDIFF(MI,start_time,end_time))

Thanks in advance for your help.

Answer 1

You're close, but you should use DateDiff() to get the average number of seconds between the two fields, rather than the average number of minutes .

With SQL Server 2008 R2 , you don't have access to TIMEFROMPARTS() which would simplify the display greatly, so you'll have to convert this into a VARCHAR to get the format you want.

;With AverageSeconds As
(
    Select  Avg(DateDiff(Second, Start_Time, End_Time))) AvgSec
    From    YourTable
)
Select  Right('00' + Convert(Varchar, (AvgSec / 60)), 2) 
             + ':' 
      + Right('00' + Convert(Varchar, (AvgSec % 60)), 2)
From    AverageSeconds

Answer 2

您可以在unixtimestamp中转换日期，然后在字符串中转换秒数。

Answer 3

另外

right(convert(varchar(20), Dateadd(second, Avg(Datediff(second, Start_Time, End_Time)), 0), 120), 5)