MySQL column type: TIMESTAMP vs DATETIME
In MySQL, both TIMESTAMP
and DATETIME
are used to store date and time values, but they have some differences in terms of behavior and storage:
-
Storage:
-
TIMESTAMP
: Stored as a Unix timestamp. It requires 4 bytes for storage, which means it can store values from ‘1970-01-01 00:00:01’ UTC to ‘2038-01-19 03:14:07’ UTC. It also automatically converts times from the current time zone to UTC for storage, and back from UTC to the current time zone for retrieval. -
DATETIME
: Stored in a human-readable format (‘YYYY-MM-DD HH:MM:SS’). It requires 8 bytes for storage and can store a wider range of dates compared toTIMESTAMP
.
-
-
Range:
-
TIMESTAMP
: Limited to the range ‘1970-01-01 00:00:01’ UTC to ‘2038-01-19 03:14:07’ UTC. -
DATETIME
: Can store dates from ‘1000-01-01 00:00:00’ to ‘9999-12-31 23:59:59’.
-
-
Behavior:
-
TIMESTAMP
: Automatically updates when the row is created or updated if not explicitly set. It also automatically converts times from the current time zone to UTC for storage and vice versa. -
DATETIME
: Does not automatically update. You need to explicitly set the value if you want to update it.
-
-
Indexing:
-
TIMESTAMP
: More efficient for indexing and querying data within a specific range due to its internal representation as a Unix timestamp. -
DATETIME
: Slower for indexing compared toTIMESTAMP
, as it stores dates in a human-readable format.
-
-
Usage:
- Use
TIMESTAMP
when you need to track when a row was created or updated, especially if you want automatic updating behavior and if you don’t need to store dates outside the range supported byTIMESTAMP
. - Use
DATETIME
when you need to store dates outside the range supported byTIMESTAMP
or when you need specific dates without automatic updating behavior.
- Use
In summary, choose between TIMESTAMP
and DATETIME
based on your specific requirements regarding range, storage size, automatic updating behavior, and indexing efficiency.