In MySQL, you can use the WEEKDAY() function to return the weekday index for a given date. Simply provide the date as an argument and the function will return the weekday index.

Syntax

The syntax goes like this:

WEEKDAY(date)

Where date is the date you want the weekday returned from.

Example 1 – Basic Usage

Here’s an example to demonstrate.

SELECT WEEKDAY('2021-01-21') AS 'Weekday';

Result:

+---------+
| Weekday |
+---------+
|       3 |
+---------+

Example 2 – Comparison with DAYNAME()

To make it easier for us to verify the results, here I run both the WEEKDAY() and DAYNAME() functions side by side.

SET @date = '2021-01-21';
SELECT 
  DAYNAME(@date) AS 'Day Name',
  WEEKDAY(@date) AS 'Weekday';

Result:

+----------+---------+
| Day Name | Weekday |
+----------+---------+
| Thursday |       3 |
+----------+---------+

Weekday Index

If you’re wondering why Thursday is only the 3rd day of the week, here’s how the weekday index is calculated:

Index	Week Day
0	Monday
1	Tuesday
2	Wednesday
3	Thursday
4	Friday
5	Saturday
6	Sunday