How can I modify my SQL query to group all data with the same weekday together?

To group all data with the same weekday together in a SQL query, you can use the `DAYOFWEEK()` function to extract the weekday from a date column and then group by that extracted weekday value. This will allow you to group all data with the same weekday together.

SELECT DAYOFWEEK(date_column) AS weekday, SUM(sales) AS total_sales
FROM your_table_name
GROUP BY weekday
ORDER BY weekday;