How to Efficiently Calculate Timestamp Differences in MySQL?

Calculating Timestamp Differences in MySQL

There are two primary approaches for determining the time difference between two timestamps in MySQL.

TIMEDIFF() and TIME_TO_SEC() Functions

The TIMEDIFF() function calculates the difference between two timestamps, returning a TIME value. To convert this value into seconds, use the TIME_TO_SEC() function. For instance:

SELECT TIME_TO_SEC(TIMEDIFF('2010-08-20 12:01:00', '2010-08-20 12:00:00')) diff;

UNIX_TIMESTAMP() Function

The UNIX_TIMESTAMP() function directly returns the number of seconds since the epoch for a given timestamp. Subtracting the timestamps yields the time difference in seconds. For example:

SELECT UNIX_TIMESTAMP('2010-08-20 12:01:00') - UNIX_TIMESTAMP('2010-08-20 12:00:00') diff;

Performance Considerations

When using the TIMESTAMP data type, the UNIX_TIMESTAMP() approach may perform marginally faster as it directly returns the stored integer value representing the time difference. Time values have a limited range, so consider this when working with larger time differences.

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