The HOUR function in MySQL is used to extract the hour from a given time or datetime expression. It returns an integer value representing the hour of the specified time.

Syntax

Here’s the basic syntax of the HOUR function:

HOUR(time)

time: This is the time or datetime value from which you want to extract the hour.

Examples

Let’s look at some examples to understand how the HOUR function works:

Extracting the hour from a datetime value

SELECT HOUR('2024-01-01 15:30:45');

This query will return 15, as it extracts the hour from the specified datetime value.

Extracting the hour from a time value

SELECT HOUR('08:45:30');

This query will return 8, as it extracts the hour from the specified time value.

Using the HOUR function in a WHERE clause

SELECT * FROM orders
WHERE HOUR(order_date) >= 12;

This query retrieves records from the “orders” table where the hour of the “order_date” is greater than or equal to 12.

Keep in mind that the HOUR function returns values in the range from 0 to 23, as hours are typically represented in a 24-hour format in MySQL.

In summary, the HOUR function is a useful tool when you need to work specifically with the hour component of a time or datetime expression in MySQL.