Surpassing MySQL's TIME value limit of 838:59:59

Question

The title might be a bit confusing so allow me to explain. I\'m using a table to record my work logs. Every day I\'ll create an entry stating from what time to what time I h

Answer 1

Counting the days separately is enough.
Here's the concatenation I used.

I illustrated with a fully copy/pastable example to ease the understanding of the limit we hit (TIME format's max value)
A free unicorn is bundled to simplify comma management

SELECT 'pq7~' AS unicorn
#######################
##  Expected result  ##
#######################
## Total, formatted as days:hh:mm:ss ##
  ,CONCAT(
    FLOOR(TIMESTAMPDIFF(SECOND, '2017-01-01 09:17:45', '2017-03-07 17:06:24') / 86400)
    , ':'
    , SEC_TO_TIME(TIMESTAMPDIFF(SECOND, '2017-01-01 09:17:45', '2017-03-07 17:06:24') % 86400)
  ) AS Real_expected_result

---

#########################
## Calculation details ##
#########################
## Extracted days from diff ##
  ,FLOOR(TIMESTAMPDIFF(SECOND, '2017-01-01 09:17:45', '2017-03-07 17:06:24') / 86400) AS Real_days
## Extracted Hours/minutes/seconds from diff ##
  ,SEC_TO_TIME(TIMESTAMPDIFF(SECOND, '2017-01-01 09:17:45', '2017-03-07 17:06:24') % 86400) AS Real_hours_minutes_seconds

---

###################################
## Demo of wrong values returned ##
###################################
  ,TIMESTAMPDIFF(SECOND, '2017-01-01 09:17:45', '2017-03-07 17:06:24') AS Real_seconds_diff

## WRONG value returned. 5.64M is truncated to 3.02 ! ##
  ,TIME_TO_SEC(SEC_TO_TIME(5644119)) AS WRONG_result

## Result is effectively limited to 838h59m59s ##
  ,SEC_TO_TIME(TIMESTAMPDIFF(SECOND, '2017-01-01 09:17:45', '2017-03-07 17:06:24')) AS Limit_hit

## Lights on said limit ##
  ,SEC_TO_TIME( 3020398) AS Limit_value_check1
  ,SEC_TO_TIME( 3020400) AS Limit_value_check2