what is mysql timestamp

mysql timestamp is a data type used to store date and time information. It has two forms: 1. TIMESTAMP type, which takes up 4 bytes of storage space. The stored value will be converted according to the time zone. , stored as UTC, the timestamp value can be updated automatically; 2. DATETIME type, which occupies 8 bytes of storage space, has no time zone conversion, and is stored directly with the inserted value. The timestamp value needs to be provided explicitly, no Automatic update function.

Operating system for this tutorial: Windows 10 system, MySQL 8 version, Dell G3 computer.

In MySQL, timestamp (Timestamp) is a data type used to store date and time information. It can represent the number of seconds between midnight Greenwich Mean Time (GMT) on January 1, 1970, and a specific point in time.

There are two forms of timestamps in MySQL: TIMESTAMP and DATETIME.

1. TIMESTAMP type:

• takes up 4 bytes of storage space.

• The range that can be represented is from 00:00:01 on January 1, 1970 to 23:59:59 on December 31, 2038 (in Greenwich Mean Time) .

• The stored value will be converted according to the time zone and stored as UTC (Coordinated Universal Time).

• When inserting or updating the TIMESTAMP column in a table, if no value is provided for the column, the current time is automatically used.

• The timestamp value can be automatically updated. For example, you can use DEFAULT CURRENT_TIMESTAMP or ON UPDATE CURRENT_TIMESTAMP to set automatic update.

• Suitable for recording information such as timestamp, creation time and modification time.

2. DATETIME type:

• occupies 8 bytes of storage space.

• The range that can be expressed is much larger than TIMESTAMP, from '1000-01-01 00:00:00' to '9999-12-31 23:59:59' (in Gregorian calendar count).

• No time zone conversion and stored directly as inserted value.

• The timestamp value needs to be provided explicitly and there is no automatic update function.

• Suitable for situations where non-UTC time, ancient or distant date ranges need to be stored.

Which type to use depends on the specific needs and business scenarios. If you only need to record information such as timestamp, creation time and modification time, you usually choose to use the TIMESTAMP type. And for situations where a wider date and time range is required, the DATETIME type can be used.

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