SQL - Select what is not in second table from assocciative - sql

Question

I have a table "person", an associative table "person_vaccination" and a table "vaccination".
I want to get the person who has missing vaccinations but so far I only got it to work when I have the id.
SELECT vac.VACCINATION_Name
FROM VACCINATION vac
WHERE vac.VACCINATION_NUMBER NOT IN
(SELECT v.VACCINATION_NUMBER
FROM PERSON per
Join PERSON_VACCINATION pv ON per.PERSON_NUMBER = pv.PERSON_NUMBER
JOIN VACCINATION v ON pv.VACCINATION_NUMBER = v.VACCINATION_NUMBER
WHERE per.PERSON_NUMBER = 6)
It works fine but how do I get all the people missing their vaccinations? (ex:
555 , Vacccination 1
555 , Vacccination 2
666 , Vacccination 1)

Answer 1

SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE VACCINATION ( VACCINATION_NUMBER, VACCINATION_NAME ) AS
SELECT 1, 'Vac 1' FROM DUAL
UNION ALL SELECT 2, 'Vac 2' FROM DUAL
UNION ALL SELECT 3, 'Vac 3' FROM DUAL
UNION ALL SELECT 4, 'Vac 4' FROM DUAL;
CREATE TABLE PERSON_VACCINATION ( VACCINATION_NUMBER, PERSON_NUMBER ) AS
SELECT 1, 1 FROM DUAL
UNION ALL SELECT 2, 1 FROM DUAL
UNION ALL SELECT 3, 1 FROM DUAL
UNION ALL SELECT 4, 1 FROM DUAL
UNION ALL SELECT 1, 2 FROM DUAL
UNION ALL SELECT 2, 2 FROM DUAL
UNION ALL SELECT 3, 2 FROM DUAL;
CREATE TABLE PERSON ( PERSON_NUMBER, PERSON_NAME ) AS
SELECT 1, 'P1' FROM DUAL
UNION ALL SELECT 2, 'P2' FROM DUAL
UNION ALL SELECT 3, 'P3' FROM DUAL;
Query 1:
SELECT p.PERSON_NAME,
v.VACCINATION_NAME
FROM VACCINATION v
CROSS JOIN
PERSON p
WHERE NOT EXISTS ( SELECT 1
FROM PERSON_VACCINATION pv
WHERE pv.VACCINATION_NUMBER = v.VACCINATION_NUMBER
AND pv.PERSON_NUMBER = p.PERSON_NUMBER )
ORDER BY p.PERSON_NAME,
p.PERSON_NUMBER,
v.VACCINATION_NAME,
v.VACCINATION_NUMBER
Results:
| PERSON_NAME | VACCINATION_NAME |
|-------------|------------------|
| P2 | Vac 4 |
| P3 | Vac 1 |
| P3 | Vac 2 |
| P3 | Vac 3 |
| P3 | Vac 4 |

Answer 2

Instead of an INNER JOIN, you should use LEFT JOIN.
Take a look at this link: http://www.w3schools.com/sql/sql_join_left.asp

Answer 3

If you are after people with no vaccinations at all, then you can use a LEFT OUTER JOIN between PERSON and PERSON_VACCINATION, then find all entries where a PERSON_VACCINATION column is NULL.
SELECT PERSON_NUMBER
FROM PERSON P
LEFT OUTER JOIN
PERSON_VACCINATION PV
ON P.PERSON_NUMBER = PV.PERSON_NUMBER
WHERE PV.PERSON_NUMBER IS NULL
If you are unfamiliar with LEFT OUTER JOIN, it tries to find matching rows in PERSON_VACCINATION for each row in PERSON. If there are no matching rows, it leaves the PERSON row in the result set, and shows NULL values for all columns in the PERSON_VACCINATION table.
If you are looking for a list of people and the vaccinations they do not have then #MT0's answer is correct. You need to create a result set containing all possible combinations of PERSON and VACCINATION (a Cross Join), then check which of those combinations actually exist in PERSON_VACCINATION. Any entry that does not exist is are your missing vaccinations.