यूनियन क्लॉज का उपयोग करके चुनें

आपको INTERSECT . का उपयोग करना चाहिए और MINUS (ओरेकल के लिए):

-- At least at Boston or at Dallas 
(SELECT DNAME 
   FROM DEPARTMENT 
  WHERE CITY = 'DALLAS'

UNION

 SELECT DNAME 
   FROM DEPARTMENT 
  WHERE CITY = 'BOSTON')

MINUS

-- At Boston and at Dallas
(SELECT DNAME 
   FROM DEPARTMENT 
  WHERE CITY = 'DALLAS'

INTERSECT

 SELECT DNAME 
   FROM DEPARTMENT 
  WHERE CITY = 'BOSTON')

चूंकि UNION जोड़ता है EXCEPT . के दौरान सबक्वायरी ऊपर /MINUS घटाना उन्हें