The TIMESTAMP data type in MySQL is used to store date and time values. It represents a specific point in time, ranging from the years 1970 to 2038. This data type is commonly used when you need to track the creation or modification time of a record in a database table.
How to Define a TIMESTAMP Column
To define a column with the TIMESTAMP data type, you can use the following syntax:
CREATE TABLE table_name (
column_name TIMESTAMP
);
Default Value of a TIMESTAMP Column
If you do not specify a default value for a TIMESTAMP column, it will be set to the current timestamp when a new row is inserted into the table. You can also explicitly set the default value using the DEFAULT CURRENT_TIMESTAMP clause.
Automatic Update of TIMESTAMP Column
In addition to setting the default value on insertion, you can also automatically update the timestamp value whenever the row is updated using the ON UPDATE CURRENT_TIMESTAMP clause. This ensures that the timestamp reflects the latest modification time.
Difference Between TIMESTAMP and DATETIME Data Types
The main difference between the TIMESTAMP and DATETIME data types in MySQL is their range and behavior. While both store date and time values, TIMESTAMP has a range of 1970 to 2038 and automatically converts values from your current time zone to UTC for storage. On the other hand, DATETIME has a wider range but does not perform any timezone conversions.
Formatting TIMESTAMP Values
When retrieving a TIMESTAMP value from the database, MySQL provides several functions to format it according to your needs. For example:
- DATE_FORMAT(timestamp_column, ‘format_string’): This function allows you to format the timestamp as per your desired format using placeholders such as %Y for the year, %m for the month, %d for the day, and so on.
- UNIX_TIMESTAMP(): This function returns the UNIX timestamp representation of a given timestamp value.
Conclusion
The TIMESTAMP data type in MySQL is a useful tool for storing and manipulating date and time values. Its ability to automatically update itself on modification and convert time zones makes it a convenient option when tracking temporal information in your database tables.