Calculate Average Time Over 24 hour period - sql

Question

I'm working in Teradata and am trying to calulate the average time a job completes.
Data Values:
Job Name Start Date End Date End Time
D_BDW_CCIP_SRM_LD 10/10/2012 10/11/2012 01:41:49
D_BDW_CCIP_SRM_LD 10/9/2012 10/10/2012 00:19:56
D_BDW_CCIP_SRM_LD 10/8/2012 10/8/2012 23:37:18
D_BDW_CCIP_SRM_LD 10/5/2012 10/5/2012 23:39:47
D_BDW_CCIP_SRM_LD 10/4/2012 10/4/2012 23:42:47
D_BDW_CCIP_SRM_LD 10/3/2012 10/3/2012 23:41:54
The average is coming back with 16:07 instead of 00:07. What I need to happen is that the calculations where the job finishes next day understands that the time expanded.
In Excel I could do this by adding one day to the end time and then averaging and displaying as a time.
How do I do this in Teradata?

Answer 1

This is such an interesting question! UPDATED with correct syntax: Assuming your START_DATE and END_DATE are DATE values and END_TIME is a TIME value, here is a solution:
select cast( avg( case
when start_date <> end_date
then extract(second from end_time)
+ extract(minute from end_time) * 60
+ extract(hour from end_time) * 3600
+ 86400
else extract(second from end_time)
+ extract(minute from end_time) * 60
+ extract(hour from end_time) * 3600
end) mod 86400) as decimal(10,4))
* INTERVAL '00:00:01.00' HOUR TO SECOND as avg_time
from your_table
The CASE expression "adds" one day (86,400 seconds) as you suggested when using Excel to determine the average seconds since midnight into an intermediate result and converted into a TIME column.
To be fair, I received help from the Teradata Forum formatting the result, but I like this so much I'll be using it myself.

Answer 2

This seems to do the trick, but I'd be interested in seeing if there is another way.
SELECT job_name,
case when avg_end_time_in_minutes > 60*24 then avg_end_time_in_minutes - 60*24
else avg_end_time_in_minutes end as avg_adjusted,
case when max_end_time_in_minutes > 60*24 then max_end_time_in_minutes - 60*24
else max_end_time_in_minutes end as max_adjusted,
CAST((CAST(avg_adjusted / 60 AS INTEGER) (FORMAT '9(2)')) AS CHAR(2))||':'||
CAST((CAST((avg_adjusted / 60 MOD 1)*60 AS INTEGER) (FORMAT '9(2)')) AS CHAR(2))
avg_adjusted_time,
CAST((CAST(max_adjusted / 60 AS INTEGER) (FORMAT '9(2)')) AS CHAR(2))||':'||
CAST((CAST((max_adjusted / 60 MOD 1)*60 AS INTEGER) (FORMAT '9(2)')) AS CHAR(2))
max_adjusted_time
FROM (
SELECT job_name,
AVG(end_time_in_minutes) avg_end_time_in_minutes,
MAX(CAST(end_time_in_minutes AS DECIMAL(8,2))) max_end_time_in_minutes
FROM (
SELECT job_name,
CAST(substr(end_time, 1, 2) AS INTEGER)*60
+ CAST(substr(end_time, 4, 2) AS INTEGER)
+ cast(end_date - start_date as integer)*60*24 AS end_time_in_minutes
FROM dabank_prod_ops_tb.bdw_tables_load_tracker_view a
WHERE a.status = 'COMPLETED'
AND a.start_date BETWEEN CURRENT_DATE - 31 AND CURRENT_DATE -1
AND a.end_time IS NOT NULL
) a
GROUP BY 1
) b

Answer 3

First, figure out the number of seconds that the end time is from midnight on the start date. We can then use that to calculate the average number of seconds taken, and then add that to midnight to find the average end time.
select
avg(extract(second from end_time) + 60 *
(extract(minute from end_time) + 60 *
(extract(hour from end_time) + 24 *
(end_date - start_date))) as avg_duration_in_seconds
cast(avg_duration_in_seconds / 60 / 60 as integer) as avg_hours
mod(cast(avg_duration_in_seconds / 60 as integer), 60) as avg_minutes
mod(cast(avg_duration_in_seconds as integer), 60) as avg_seconds,
cast('00:00:00' as time) +
cast(avg_hours as interval hour) +
cast(avg_minutes as interval minute) +
cast(avg_seconds as interval second) as avg_end_time
from my_table
Be aware though that if the average ends up over 24 hours, avg_end_time will be something like 00:01:15 rather than 24:01:15.