How to Add a Timestamp Column with Default Values in MySQL

Learn how to use the `ALTER TABLE` statement in MySQL to add a `timestamp` column with default values for both new and existing records.
---
How to Add a Timestamp Column with Default Values in MySQL

In MySQL, maintaining accurate records often includes keeping track of when data entries are created or updated. This is where a timestamp column can become highly valuable. By adding a timestamp column, you can have a clear view of the timing associated with each record's creation and modification.

Using ALTER TABLE to Add a Timestamp Column

To add a timestamp column to an existing table and ensure it has default values for both new and current records, you can use the ALTER TABLE statement. Here's how you can get this done:

Syntax Overview

[[See Video to Reveal this Text or Code Snippet]]

In this command:

table_name is the name of your existing table.

column_name is the name of the new timestamp column you want to add.

DEFAULT CURRENT_TIMESTAMP ensures that the timestamp is automatically set to the current date and time when a new record is inserted.

Example

Suppose you have a table named orders. To add a timestamp column named created_at with default values, use the following SQL statement:

[[See Video to Reveal this Text or Code Snippet]]

This command will successfully add the created_at column to the orders table. For every new record inserted into this table, created_at will be set to the current date and time automatically.

Updating Existing Records

What if you have existing records and you want to set a default timestamp for them? After adding the timestamp column, you can update existing records by setting them with a desired timestamp value. Here's an example to set the current timestamp for all existing rows:

[[See Video to Reveal this Text or Code Snippet]]

This command will ensure that any existing record without a timestamp in the created_at column will be updated to the current date and time.

Conclusion

Adding a timestamp column with default values in MySQL can enhance your ability to manage and audit data. Using the ALTER TABLE statement allows you to seamlessly integrate this feature into your existing tables. This not only simplifies the management of new records but also ensures historical data reliability.

Adopting these practices can significantly improve data integrity and provide a more thorough insight into your records' lifecycle.