MySql difference between two timestamps in Seconds?

Question

Is it possible to calculate difference between two timestamps in Mysql and get output result in seconds? like 2010-11-29 13:16:55 - 2010-11-29 13:13:55 should give 180 seconds.

Thank you

Answer 1

I do not think the accepted answer is a good universal solution!

This is because the UNIX_TIMESTAMP() function fails for DATEs before 1970-01-01 (and for dates in the far future using 32 bit integers). This may happen easily for the day of birth of many living people.

A better solution is:

SELECT TIMESTAMPDIFF(SECOND, '2010-11-29 13:13:55', '2010-11-29 13:16:55') 

Which can be modified to return DAY YEAR MONTH HOUR and MINUTE too!

Answer 2

Use the UNIX_TIMESTAMP function to convert the DATETIME into the value in seconds, starting from Jan 1st, 1970:

SELECT UNIX_TIMESTAMP('2010-11-29 13:16:55') - UNIX_TIMESTAMP('2010-11-29 13:13:55') as output 

Result:

output ------- 180 

An easy way to deal with if you're not sure which value is bigger than the other -- use the ABS function:

SELECT ABS(UNIX_TIMESTAMP(t.datetime_col1) - UNIX_TIMESTAMP(t.datetime_col2)) as output