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MySQL - convert date to weekday number

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Created by:

Emelia

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In this article, we would like to show you how to convert date to weekday number in MySQL.

Quick solution:

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SELECT DAYOFWEEK(date_expression) AS 'dayofweek';

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SELECT WEEKDAY(date_expression) AS 'weekday';

Note:

Go to this article to read about differences between DAYOFWEEK() and WEEKDAY() functions.

Simple example

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In this example, we will convert example date ( 2021-01-01 11:41:31 - Friday) to weekday number.

`DAYOFWEEK()` example

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Query:

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SELECT DAYOFWEEK('2021-01-01 11:41:31') AS 'dayofweek';

Result:

`WEEKDAY()` example

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Query:

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SELECT WEEKDAY('2021-01-01 11:41:31') AS 'weekday';

Result:

Practical example

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To show how to convert date to weekday number, we will use the following table:

MySQL - example data used to convert date to weekday number

Note:

At the end of this article you can find database preparation SQL queries.

Example 1 - `DAYOFWEEK()` function

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In this example, we will convert registration_time column from users table to the day week number using DAYOFWEEK() function.

Query:

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SELECT
    `id`, `username`, `registration_time`, 
    DAYOFWEEK(`registration_time`) AS 'dayofweek'
FROM `users`;

Result:

Example 2 - `WEEKDAY()` function

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In this example, we will convert registration_time column from users table to the day week number using WEEKDAY() function.

Query:

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SELECT
    `id`, `username`, `registration_time`, 
    WEEKDAY(`registration_time`) AS 'weekday'
FROM `users`;

Result:

Database preparation

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create_tables.sql file:

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CREATE TABLE `users` (
    `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    `username` VARCHAR(50) NOT NULL,
    `registration_time` DATETIME NOT NULL,
    PRIMARY KEY (`id`)
);

insert_data.sql file:

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INSERT INTO `users`
    (`username`, `registration_time`)
VALUES
    ('Tom', '2021-01-01 11:41:31'),
    ('Chris','2021-01-02 11:42:45'),
    ('Jack','2021-01-03 15:13:39'),
    ('Kim','2021-01-03 15:24:51'),
    ('Marco','2021-01-04 22:35:38'),
    ('Kate','2021-01-04 22:46:51'),
    ('Nam','2021-01-04 22:57:37');