SQL Server - complete results with non existent data - sql

Question

I have a table where I have all the customers and a table where I have all their restrictions.
CUSTOMER
customer_id customer_name
1 name 1
2 name 2
CUSTOMER_RESTRICTIONS
rest_type day_of_week hour_start hour_stop customer_id
TYPE1 0 08:00 12:00 1
TYPE1 0 13:00 17:00 1
TYPE2 0 17:00 23:59 1
Problem: I only have a record for a restriction type and a customer when the customer has a restriction and this is a problem in the visualization I want to build.
I need every customer, every day and every restriction type, even when there is no restriction. In that case hour_start and hour_stop would be NULL.
For the tables shown, the output would be
rest_type day_of_week hour_start hour_stop customer_id
TYPE1 0 08:00 12:00 1
TYPE1 0 08:00 12:00 1
TYPE1 1 NULL NULL 1
TYPE1 2 NULL NULL 1
TYPE1 3 NULL NULL 1
TYPE1 4 NULL NULL 1
TYPE1 5 NULL NULL 1
TYPE1 6 NULL NULL 1
TYPE1 1 NULL NULL 1
TYPE1 2 NULL NULL 1
TYPE1 3 NULL NULL 1
TYPE1 4 NULL NULL 1
TYPE1 5 NULL NULL 1
TYPE2 0 NULL NULL 1
TYPE2 1 NULL NULL 1
TYPE2 2 NULL NULL 1
TYPE2 3 NULL NULL 1
TYPE2 4 NULL NULL 1
TYPE2 5 NULL NULL 1
TYPE2 6 NULL NULL 1
TYPE1 0 NULL NULL 2
TYPE1 1 NULL NULL 2
TYPE1 2 NULL NULL 2
TYPE1 3 NULL NULL 2
TYPE1 4 NULL NULL 2
TYPE1 5 NULL NULL 2
TYPE1 6 NULL NULL 2
TYPE2 0 NULL NULL 2
TYPE2 1 NULL NULL 2
TYPE2 2 NULL NULL 2
TYPE2 3 NULL NULL 2
TYPE2 4 NULL NULL 2
TYPE2 5 NULL NULL 2
TYPE2 6 NULL NULL 2
How can I achieve that? I couldn't even start to build this query.

Answer 1

Essentially you need to start with the data you must have and left join the optional data. E.g., something like this:
select c.customer_id
,r.[rest_type]
,d.[day_of_week]
,r.[hour_start]
,r.[hour_stop]
from CUSTOMER c
cross apply (
select 0 as day_of_week
union all select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6
) d
left join CUSTOMER_RESTRICTIONS r on c.customer_id = r.customer_id and d.day_of_week = r.day_of_week
Output:
customer_id rest_type day_of_week hour_start hour_stop
----------- --------- ----------- ---------- ---------
1 TYPE1 0 08:00 12:00
1 TYPE1 0 13:00 17:00
1 TYPE2 0 17:00 23:59
1 NULL 1 NULL NULL
1 NULL 2 NULL NULL
1 NULL 3 NULL NULL
1 NULL 4 NULL NULL
1 NULL 5 NULL NULL
1 NULL 6 NULL NULL
If there are only type rest_types, you don't have a lookup table for them, and you want to show a row for each, you would do:
select c.customer_id
,t.[rest_type]
,d.[day_of_week]
,r.[hour_start]
,r.[hour_stop]
from CUSTOMER c
cross apply (
select 0 as day_of_week
union all select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6
) d
cross apply (
select 'TYPE1' as rest_type
union all select 'TYPE2'
) t
left join CUSTOMER_RESTRICTIONS r on c.customer_id = r.customer_id
and d.day_of_week = r.day_of_week
and t.rest_type = r.rest_type

Answer 2

(select rest_type, day_of_week,
hour_start ,
hour_stop
from table A
where rest_type IS NOT NULL)
Union
(select rest_type,
day_of_week,
NULL ,NULL
from table A
where rest_type IS NULL)
Is this what you want ?

Answer 3

First off, I wouldn't store rest type as you are, that is a bad habit, it should be a reference table!
You need to cross apply to get all your possible combinations, and then add in the values you DO have...
DECLARE #Customer TABLE (Id INT IDENTITY(1,1), Name NVARCHAR(100))
DECLARE #Rest TABLE (Id INT IDENTITY(1,1), Name NVARCHAR(100))
DECLARE #Restrictions TABLE (Id INT IDENTITY(1,1), RestID INT, CustomerID INT, Day_of_Week TINYINT, hour_start TIME, hour_end TIME)
INSERT INTO #Customer (NAME)
VALUES('JOHN'),('SUSAN')
INSERT INTO #Rest (NAME)
VALUES ('TYPE A'),('TYPE B')
INSERT INTO #Restrictions (RestID,CustomerID,Day_of_Week,hour_start,hour_end)
VALUES (1,1,0,'08:00','12:00'),
(1,1,0,'13:00','17:00'),
(1,2,0,'17:00','23:59')
;WITH DaysofWeek AS
(
SELECT 0 AS dow
UNION ALL
SELECT dow+1
FROM DaysofWeek
WHERE dow<5
)
SELECT *
FROM #Customer C
CROSS APPLY #Rest R
CROSS APPLY DaysofWeek D
LEFT JOIN #Restrictions X
ON X.Day_of_Week=D.dow
AND X.CustomerID=C.Id
AND X.RestID=R.Id
ORDER BY C.Id, D.dow, R.Id