1033
google search
Google search results:
1: https://compsciedu.com/DBMS/GATE-cse-question-paper/discussion/6872
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2: https://www.geeksforgeeks.org/gate-gate-cs-2000-question-48/
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3: https://testbook.com/question-answer/given-relations-rw-x-and-sy-z-the-result-of--5e8364c2f60d5d7277ffb7c3
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4: https://gateoverflow.in/672/gate-cse-2000-question-2-25
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5: http://infolab.stanford.edu/~ullman/fcdb/aut02/fsol.html
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6: http://www.nyu.edu/classes/jcf/CSCI-GA.2433-001_sp15/slides/session5/RelationalAlgebra-RelationalCalculus-SQL.pdf
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7: https://www.oreilly.com/library/view/sql-and-relational/9780596155865/ch04.html
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8: https://books.google.com/books?id=apr_DwAAQBAJ&pg=PA213&lpg=PA213&dq=Given+relations+r(w,+x)+and+s(y,+z),+the+result+of%0AO+r+and+s+have+the+same+number+of+tuples%0Aselect+distinct+w,+x%0AO+s+has+no+duplicates+and+r+is+non-empty%0Afrom+r,+s%0Ais+guaranteed+to+be+same+as+r,+provided%0AO+r+has+no+duplicates+and+s+is+non-empty%0AO+r+and+s+have+no+duplicates&source=bl&ots=7mLM2ce-2b&sig=ACfU3U36c0b7zgLznfiUZ47ywCKX_3KwuA&hl=en&sa=X&ved=2ahUKEwjy7qei2LLzAhUCvZ4KHUToDmYQ6AF6BAgSEAM
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9: https://en.wikipedia.org/wiki/Relational_algebra
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10: https://books.google.com/books?id=-Kw4DwAAQBAJ&pg=PA200&lpg=PA200&dq=Given+relations+r(w,+x)+and+s(y,+z),+the+result+of%0AO+r+and+s+have+the+same+number+of+tuples%0Aselect+distinct+w,+x%0AO+s+has+no+duplicates+and+r+is+non-empty%0Afrom+r,+s%0Ais+guaranteed+to+be+same+as+r,+provided%0AO+r+has+no+duplicates+and+s+is+non-empty%0AO+r+and+s+have+no+duplicates&source=bl&ots=K5B3YNnRKz&sig=ACfU3U1RMGEvHZVvHLPn9rwLtNqmXhDQoA&hl=en&sa=X&ved=2ahUKEwjy7qei2LLzAhUCvZ4KHUToDmYQ6AF6BAgREAM
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11: https://www.cs.ucdavis.edu/~green/courses/ecs165a-w11/3-ra.pdf
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