Limit some specific day in a week? - mysql

Question

I have bunch of dates in my database, and now I want to use WHERE to limit a specific day in a week for eg. the date I have rn is 2019-01-01 etc. and I only want to see Monday, Tuesday and Wednesday among those date. How do I do that?
The code I showed below does not work just as a reference what I'm doing rn
CREATE VIEW weekend_reservation AS
SELECT CONCAT(last_name,',',first_name) AS "guest's name",
CONCAT(DATE_FORMAT(check_in_date,"%W,%M %d,%Y")) AS 'check_in_date',
CONCAT(DATE_FORMAT(check_out_date,"%W,%M %d,%Y")) AS 'check_out_date'
FROM guests JOIN reservations
USING(guest_id)
WHERE check_in_date BETWEEN 'Friday' AND 'Sunday'
ORDER BY check_in_date,check_out_date,last_name,first_name;

Answer 1

Well, I wouldn't do it just by changing the SELECT to have the day-of-the-week.
Instead:
CREATE VIEW weekend_reservation AS
SELECT CONCAT_WS(',', g.last_name, g.first_name) AS "guest's name",
DATE_FORMAT(r.check_in_date, '%W, %M %d,%Y')) AS check_in_date,
DATE_FORMAT(r.check_out_date, '%W,%M %d,%Y')) AS check_out_date
FROM guests g JOIN
reservations r
USING (guest_id)
WHERE DAYOFWEEK(r.check_in_date) IN (6, 7, 1)
ORDER BY check_in_date, check_out_date, last_name, first_name;
Notes:
CONCAT() after the DATE_FORMAT() does nothing.
The DAYOFWEEK() function returns days, with Sunday as 1 and Saturday as 7.
You should qualify all column names (i.e. use table alias), especially when a query has more than one table reference.
CONCAT_WS() is handy. It handles NULL values better than CONCAT().