create view for items not in list - sql

Question

I have two tables. Table 1 is a master list of equipment with equipment_id and equipment_description. So, let's say for this table I have ten equipment_id's. 1,2,3....10 each with some description attached.
Table 2 logs when the equipment has been inspected:
equipment_id|inspection_date
1 | '1-22-2012'
2 | '1-22-2012'
4 | '1-22-2012'
2 | '1-23-2012'
3 | '1-23-2012'
I've created a view, v_dates which pulls out of table 2 all of the distinct inspection dates - not sure if I needed it but did it anyway.
I would like to create another view which shows all equipment that was NOT inspected for each date in the v_dates. So it would show:
3 | '1-22-2012'
5 | '1-22-2012'
and so on.
Rookie here and just not sure how to join these tables correctly. Can't get it to work and would appreciate any help.

Answer 1

Untested, but I think this should give the desired result:
SELECT i.id,d.date FROM
( SELECT DISTINCT inspection_date AS date FROM inspections ORDER BY 1 ) d
LEFT JOIN
inspections i
ON d.date=i.date
WHERE i.date IS NULL
GROUP BY 1,2
ORDER BY 1,2
Like mentioned in the comments would a table with inspection dates really help.

Answer 2

The following appears to work based on my test data using SQL SERVER 2005. I am using a CROSS JOIN of distinct dates along with a LEFT JOIN to throw out EQUIPMENT_ID records that exist for those dates.
Sorry, I am having problems getting my code formatting correct with tabs and spaces...
IF OBJECT_ID('tempdb..#EQUIPMENT') IS NOT NULL
DROP TABLE #EQUIPMENT
CREATE TABLE #EQUIPMENT
( EQUIPMENT_ID smallint,
EQUIPMENT_DESC varchar(32)
)
INSERT INTO #EQUIPMENT
( EQUIPMENT_ID, EQUIPMENT_DESC )
SELECT 1, 'AAA'
UNION SELECT 2, 'BBB'
UNION SELECT 3, 'CCC'
UNION SELECT 4, 'DDD'
UNION SELECT 5, 'EEE'
UNION SELECT 6, 'FFF'
UNION SELECT 7, 'GGG'
UNION SELECT 8, 'HHH'
UNION SELECT 9, 'III'
UNION SELECT 10, 'JJJ'
IF OBJECT_ID('tempdb..#INSPECTION') IS NOT NULL
DROP TABLE #INSPECTION
CREATE TABLE #INSPECTION
( EQUIPMENT_ID smallint,
INSPECTION_DATE smalldatetime
)
INSERT INTO #INSPECTION
( EQUIPMENT_ID, INSPECTION_DATE )
SELECT 1, '1-22-2012'
UNION SELECT 1, '1-27-2012'
UNION SELECT 3, '1-27-2012'
UNION SELECT 5, '1-29-2012'
UNION SELECT 7, '1-22-2012'
UNION SELECT 7, '1-27-2012'
UNION SELECT 7, '1-29-2012'
SELECT E.EQUIPMENT_ID, D.INSPECTION_DATE
FROM #EQUIPMENT E
CROSS JOIN ( SELECT DISTINCT INSPECTION_DATE
FROM #INSPECTION
) D
LEFT JOIN #INSPECTION I2
ON E.EQUIPMENT_ID = I2.EQUIPMENT_ID
AND D.INSPECTION_DATE = I2.INSPECTION_DATE
WHERE I2.EQUIPMENT_ID IS NULL
ORDER BY E.EQUIPMENT_ID, D.INSPECTION_DATE

Answer 3

As per my comment to the question, you really need a table of valid inspection dates. It makes the sql much more sensible, and besides it's the only way to do it if you want to see all items listed for dates when inspections were supposed to be done, but no inspections were done.
So, assuming the two tables:
create table inspections (equipment_id int, inspection_date date);
create table inspection_dates (id int, inspection_date date);
Then a join to get all the equipment that does not have an inspection on a date when an inspection should have taken place would be:
select i.equipment_id, id.inspection_date
from inspection_dates id,
(select distinct equipment_id from inspections) i
where not exists (select * from inspections i2
where i2.inspection_date = id.inspection_date
and i2.equipment_id = i.equipment_id);
You want the combos that do not exist. Thus the not exists predicate.
Note again, that presumably you would have a table for all the unique equipment_ids, but not knowing that I had to construct it myself in place.