18 real Set Operations questions from the SQL bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is UNION?
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A.an operator that combines two result sets into one and removes duplicate rows from the combined output
B.an operator that concatenates two result sets keeping every row including duplicates and runs faster because no de-duplication pass is performed
C.the requirement that both queries combined by a set operator have the same number of columns with matching or coercible data types in the same order
D.a set operator (called MINUS in Oracle) returning rows present in the first result set but absent from the second
A.UNION — a set operator (called MINUS in Oracle) returning rows present in the first result set but absent from the second
B.UNION — an operator that concatenates two result sets keeping every row including duplicates and runs faster because no de-duplication pass is performed
C.UNION — the rule that a sort clause applies to the whole combined result and therefore must appear once at the end rather than inside the individual queries
D.UNION — an operator that combines two result sets into one and removes duplicate rows from the combined output
5. Which term means: "an operator that concatenates two result sets keeping every row including duplicates and runs faster because no de-duplication pass is performed"?
A.UNION ALL — the requirement that both queries combined by a set operator have the same number of columns with matching or coercible data types in the same order
B.UNION ALL — an operator that concatenates two result sets keeping every row including duplicates and runs faster because no de-duplication pass is performed
C.UNION ALL — a set operator returning only the rows that appear in both of the two input result sets
D.UNION ALL — an operator that combines two result sets into one and removes duplicate rows from the combined output
A.INTERSECT — a set operator returning only the rows that appear in both of the two input result sets
B.INTERSECT — a set operator (called MINUS in Oracle) returning rows present in the first result set but absent from the second
C.INTERSECT — the rule that a sort clause applies to the whole combined result and therefore must appear once at the end rather than inside the individual queries
D.INTERSECT — an operator that combines two result sets into one and removes duplicate rows from the combined output
A.EXCEPT — the rule that a sort clause applies to the whole combined result and therefore must appear once at the end rather than inside the individual queries
B.EXCEPT — an operator that concatenates two result sets keeping every row including duplicates and runs faster because no de-duplication pass is performed
C.EXCEPT — a set operator returning only the rows that appear in both of the two input result sets
D.EXCEPT — a set operator (called MINUS in Oracle) returning rows present in the first result set but absent from the second
14. Which term means: "the requirement that both queries combined by a set operator have the same number of columns with matching or coercible data types in the same order"?
A.column-compatibility rule — a set operator (called MINUS in Oracle) returning rows present in the first result set but absent from the second
B.column-compatibility rule — the rule that a sort clause applies to the whole combined result and therefore must appear once at the end rather than inside the individual queries
C.column-compatibility rule — the requirement that both queries combined by a set operator have the same number of columns with matching or coercible data types in the same order
D.column-compatibility rule — an operator that combines two result sets into one and removes duplicate rows from the combined output
17. Which term means: "the rule that a sort clause applies to the whole combined result and therefore must appear once at the end rather than inside the individual queries"?
A.set-operation ORDER BY placement — an operator that combines two result sets into one and removes duplicate rows from the combined output
B.set-operation ORDER BY placement — the rule that a sort clause applies to the whole combined result and therefore must appear once at the end rather than inside the individual queries
C.set-operation ORDER BY placement — an operator that concatenates two result sets keeping every row including duplicates and runs faster because no de-duplication pass is performed
D.set-operation ORDER BY placement — the requirement that both queries combined by a set operator have the same number of columns with matching or coercible data types in the same order
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