केवल विशेष विभागों से संबंधित उपयोगकर्ताओं का चयन करें

यह एक रिलेशनल डिवीजन है जिसमें कोई अवशेष नहीं है (RDNR) संकट। इसे देखें लेख ड्वेन कैंप द्वारा जो इस तरह की समस्या के कई समाधान प्रदान करता है।

पहला समाधान

SQL Fiddle

SELECT empId
FROM (
    SELECT
        empID, cc = COUNT(DISTINCT department)
    FROM employe
    WHERE department IN('Y', 'Z')
    GROUP BY empID
)t
WHERE
    t.cc = 2
    AND t.cc = (
        SELECT COUNT(*)
        FROM employe
        WHERE empID = t.empID
    )

दूसरा समाधान

SQL Fiddle

SELECT e.empId
FROM employe e
WHERE e.department IN('Y', 'Z')
GROUP BY e.empID
HAVING
    COUNT(e.department) = 2
    AND COUNT(e.department) = (SELECT COUNT(*) FROM employe WHERE empID = e.empId)

GROUP BY using का उपयोग किए बिना और HAVING :

SELECT DISTINCT e.empID
FROM employe e
WHERE
    EXISTS(
        SELECT 1 FROM employe WHERE department = 'Z' AND empID = e.empID
    )
    AND EXISTS(     
        SELECT 1 FROM employe WHERE department = 'Y' AND empID = e.empID
    )
    AND NOT EXISTS(
        SELECT 1 FROM employe WHERE department NOT IN('Y', 'Z') AND empID = e.empID
    )