Join logic from two separate tables in sql - sql

Question

We returned a list of cardID's after a query and those cardID's belong to two tables Student and Personnel. So how can I join those cardID's with Student and Personnel so I can return a table that shows name of Student and Personnel according to cardID's?
Personnel table:
PERSONNELID NUMBER(9,0)
PERSONNELNAME VARCHAR2(20)
PERSONNELSURNAME VARCHAR2(20)
PERSONNELJOB VARCHAR2(40)
PERSONNELCARDID NUMBER(4,0)
Student table:
STUDENTID NUMBER(9,0)
STUDENTNAME VARCHAR2(20)
STUDENTSURNAME VARCHAR2(20)
STUDENTDEPT VARCHAR2(40)
STUDENTFACULTY VARCHAR2(20)
STUDENTCARDID NUMBER(4,0)
CardID table
CARDID NUMBER(4,0)
USERTYPE VARCHAR2(20)
CHARGE NUMBER(3,2)
CREDIT NUMBER(4,2)
PaymentDevice table:
ORDERNO NUMBER
PAYDEVIP NUMBER(8,0)
PAYDEVDATE DATE No
PAYDEVTIME VARCHAR2(8)
CHARGEDCARDID NUMBER(9,0)
MEALTYPE VARCHAR2(10)
I tried to return first 10 person's name and surname that eat at cafeteria on 27/12/2012
SELECT C.CARDID
FROM CARD C, PAYMENTDEVICE P
WHERE P.ORDERNO
BETWEEN (SELECT MIN(ORDERNO)
FROM PAYMENTDEVICE
WHERE PAYDEVDATE='27/12/2012') AND (SELECT MIN(ORDERNO)
FROM PAYMENTDEVICE
WHERE PAYDEVDATE='27/12/2012')+10 AND C.CARDID=P.CHARGEDCARDID;
Our orderNo isn't reset everyday but keeps increasing so we found the min orderNo that day and add 10 to this value to find first 10 person who eat on that day between those order numbers.
So what return from this query:
CARDID
1005
1000
1002
1003
1009
2000
2001
1007
2002
1004
1006
and those some of those cardId (start with 1) are studentCardId and some of them (starts with 2) are PersonnelCardId. So how can I match and write names accordingly?

Answer 1

SELECT *
FROM Personel p INNER JOIN Student s
ON p.PersonnelCardId = s.StudentCardId
INNER JOIN ReturnedQuery rq
ON rq.CardId = p.PersonnelCardId
updated:
SELECT p.PersonnelName, rq.CardId
FROM Personel p INNER JOIN ReturnedQuery rq
ON rq.CardId = p.PersonnelCardId
UNION
SELECT s.StudentName, rq.Cardid
FROM Student s INNER JOIN ReturnedQuery rq
ON s.StudentCardId = rq.Cardid

Answer 2

Your original query is actually pretty fragile. I'd rewrite it like so (and added the needed joins):
WITH First_Daily_Purchase as (SELECT chargedCardId,
MIN(payDevTime) as payDevTime,
MIN(orderNo) as orderNo
FROM PaymentDevice
WHERE payDevDate >=
TO_DATE('2012-12-27', 'YYYY-MM-DD')
AND payDevDate <
TO_DATE('2012-12-28', 'YYYY-MM-DD')
GROUP BY chargedCardId),
First_10_Daily_Purchasers as (SELECT chargedCardId
FROM (SELECT chargedCardId,
RANK() OVER(ORDER BY payDevTime,
orderNo) as rank
FROM First_Daily_Purchase) a
WHERE a.rank < 11)
SELECT a.chargedCardId, b.personnelName, b.personnelSurname
FROM First_10_Daily_Purchasers a
JOIN Personnel b
ON b.personnelCardId = a.chargedCardId
UNION ALL
SELECT a.chargedCardId, b.studentName, b.studentSurname
FROM First_10_Daily_Purchasers a
JOIN Student b
ON b.studentCardId = a.chargedCardId
(Have a working SQL Fiddle - generally bullet-proofing this took me a while.)
This should get you the first 10 people who made a purchase (not the first 11 purchases, which is what you were actually getting). This of course assumes that payDevTime is actually stored in a sortable format (if it isn't you have bigger problems than this query not working quite right).
That said, there's a number of troubling things about your schema design.