MySQL Check if Business Hours Exist for Each Day of the Week

Question

I need a query to check if the business has business hours set for EACH day of the week (dayofweek IDs are 1-7)

It will be used something like this:

hours_check = MySQL query will check if hours exists for each day of the week

if hours_check true:
    return X 
else:
    return Y

I have these 3 tables:

BUSINESS
id ..
name ..

DAYOFWEEK
id ..
name ..

HOURS
id ..
business_id ..
dayofweek_id .. 

I know how to check for one day with something like:

SELECT EXISTS(SELECT id FROM hours WHERE business_id = 1 and dayofweek_id = 1)

How do I check for each day without running a separate query for each day?

Answer 1

Try this:

create table BUSINESS ( id   int NOT NULL AUTO_INCREMENT primary key, 
                        name char(20) );
create table DAYOFWEEK ( id   int not NULL, 
                         name char(3) );
create table HOURS ( id           int NOT NULL AUTO_INCREMENT primary key, 
                     business_id  int NOT NULL references BUSINESS(id),
                     dayofweek_id int NOT NULL references DAYOFWEEK(id),
                     hour_range   char(20) );

insert into BUSINESS (id, name) values (1000, 'Walmart'), 
                                       (1001, 'RadioShack'), 
                                       (1002, 'AlwaysClosed');

insert into DAYOFWEEK (id, name) values 
    (1,'Mon'), (2,'Tue'), (3,'Wed'), (4,'Tue'),
    (5,'Fri'), (6,'Sat'), (7,'Sun');

insert into HOURS (business_id, dayofweek_id, hour_range) values
    (1000, 2, '08:00 - 10:00'),    
    (1000, 2, '12:00 - 19:00'),
    (1000, 6, '09:00 - 21:00'),
    (1001, 3, '07:00 - 17:00');

-- Get an overview which shop is open when:
select b.name, d.name as day, h.hour_range 
  from HOURS h inner join DAYOFWEEK d on h.dayofweek_id=d.id
       left join BUSINESS b on b.id=h.business_id
       order by b.name, d.id, h.hour_range;

-- Get an overview for each day:
select d.name as day, b.name, h.hour_range 
  from DAYOFWEEK d left join HOURS h on h.dayofweek_id=d.id
       left join BUSINESS b on b.id=h.business_id
       order by d.id, b.name, h.hour_range;

The two selects will result in

+------------+------+---------------+
| name       | day  | hour_range    |
+------------+------+---------------+
| RadioShack | Wed  | 07:00 - 17:00 |
| Walmart    | Tue  | 08:00 - 10:00 |
| Walmart    | Tue  | 12:00 - 19:00 |
| Walmart    | Sat  | 09:00 - 21:00 |
+------------+------+---------------+
4 rows in set (0.00 sec)

and

+------+------------+---------------+
| day  | name       | hour_range    |
+------+------------+---------------+
| Mon  | NULL       | NULL          |
| Tue  | Walmart    | 08:00 - 10:00 |
| Tue  | Walmart    | 12:00 - 19:00 |
| Wed  | RadioShack | 07:00 - 17:00 |
| Tue  | NULL       | NULL          |
| Fri  | NULL       | NULL          |
| Sat  | Walmart    | 09:00 - 21:00 |
| Sun  | NULL       | NULL          |
+------+------------+---------------+
8 rows in set (0.00 sec)

Answer 2

You could use the SQL IN operator .

SELECT 
EXISTS(
    SELECT id FROM hours WHERE business_id = 1 and dayofweek_id IN [1,2,3..etc]
)

Assuming you just want to make sure that there exists an hour during the week that they are open.

Answer 3

Something like this:

select hours.*, dayofweek.name AS day
from dayofweek
inner join hours on hours.dayofweek_id = dayofweek.id
where hours.business_id = 1