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:

  1. 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 to TIMESTAMP.
  2. 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’.
  3. 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.
  4. 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 to TIMESTAMP, as it stores dates in a human-readable format.
  5. 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 by TIMESTAMP.
    • Use DATETIME when you need to store dates outside the range supported by TIMESTAMP or when you need specific dates without automatic updating behavior.

In summary, choose between TIMESTAMP and DATETIME based on your specific requirements regarding range, storage size, automatic updating behavior, and indexing efficiency.