Avg Time difference in mysql

Question

Is there a function to find average time difference in the standard time format in my sql.

Answer 1

I was curious if AVG() was accurate or not, the way that COUNT() actually just approximates the value ("this value is an approximation"). After all, let's review the average formula: average = sum / count. So, knowing that the count is accurate is actually really important for this formula!

After testing multiple combinations, it definitely seems like AVG() works and is a great approach. You can calculate yourself to see if it's working with...

SELECT
    COUNT(id) AS count,
    AVG(TIMESTAMPDIFF(SECOND, OrigDateTime, LastDateTime)) AS avg_average,
    SUM(TIMESTAMPDIFF(SECOND, OrigDateTime, LastDateTime)) / (select COUNT(id) FROM yourTable) as calculated_average,
    AVG(TIME_TO_SEC(TIMEDIFF(LastDateTime,OrigDateTime))) as timediff_average,
    SEC_TO_TIME(AVG(TIME_TO_SEC(TIMEDIFF(LastDateTime, OrigDateTime)))) as date_display
FROM yourTable

Sample Results:

             count: 441000
       avg_average: 5045436.4376
calculated_average: 5045436.4376
  timediff_average: 5045436.4376
      date_display: 1401:30:36

Seems to be pretty accurate!

This will return:

• count: The count.
• avg_average: The average based on AVG(). (Thanks to Eric for their answer on this!)
• calculated_average: The average based on SUM()/COUNT().
• timediff_avg: The average based on TIMEDIFF(). (Thanks to Andrew for their answer on this!)
• date_display: A nicely-formatted display version. (Thanks to C S for their answer on this!)