WEEKDAY

Description

The WEEKDAY function returns the weekday index value of a date, where Monday is 0, Tuesday is 1, and Sunday is 6.

Note the difference between WEEKDAY and DAYOFWEEK:

          +-----+-----+-----+-----+-----+-----+-----+
          | Sun | Mon | Tues| Wed | Thur| Fri | Sat |
          +-----+-----+-----+-----+-----+-----+-----+
  weekday |  6  |  0  |  1  |  2  |  3  |  4  |  5  |
          +-----+-----+-----+-----+-----+-----+-----+
dayofweek |  1  |  2  |  3  |  4  |  5  |  6  |  7  |
          +-----+-----+-----+-----+-----+-----+-----+

This function behaves consistently with the weekday function in MySQL.

Syntax

WEEKDAY(`<date_or_time_expr>`)

Parameters

Parameter	Description
<datetime_or_date>	Input datetime value, supports date/datetime types. For datetime and date formats, please refer to datetime conversion and date conversion

Return Value

Returns the index corresponding to the weekday of the date, type INT.

• If input is NULL, returns NULL

Examples

-- 2023-10-09 is Monday, returns 0
SELECT WEEKDAY('2023-10-09'); 
+-------------------------+
| WEEKDAY('2023-10-09')   |
+-------------------------+
| 0                       |
+-------------------------+

-- 2023-10-15 is Sunday, returns 6
SELECT WEEKDAY('2023-10-15 18:30:00'); 
+----------------------------------+
| WEEKDAY('2023-10-15 18:30:00')   |
+----------------------------------+
| 6                                |
+----------------------------------+

-- Input is NULL, returns NULL
SELECT WEEKDAY(NULL);
+---------------+
| WEEKDAY(NULL) |
+---------------+
|          NULL |
+---------------+