54 DBMS · SQL questions from the Computer Science Fundamentals bank, written for Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd.
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A.the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT
B.a clause that collapses rows sharing a value into summary groups for aggregation
C.the SQL category for defining schema with commands like CREATE, ALTER and DROP
D.a clause that filters individual rows before any grouping is applied
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2. Which term means: "the SQL category for defining schema with commands like CREATE, ALTER and DROP"?
Junior
A.DDL
B.DML
C.Left outer join
D.GROUP BY clause
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3. Which statement is correct?
Junior
A.DDL — the SQL category for defining schema with commands like CREATE, ALTER and DROP
B.DDL — a join returning only the rows that have matching values in both tables
C.DDL — a join producing the Cartesian product of every row in one table with every row in another
D.DDL — a join in which a table is joined to itself to relate its own rows
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4. What is DML?
Junior
A.a join returning all rows from both tables, filling nulls where there is no match
B.a join producing the Cartesian product of every row in one table with every row in another
C.a subquery that references the outer query and re-executes for each outer row
D.the SQL category for manipulating data with commands like INSERT, UPDATE and DELETE
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5. Which term means: "the SQL category for manipulating data with commands like INSERT, UPDATE and DELETE"?
Junior
A.DML
B.Cross join
C.UNION operator
D.Left outer join
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6. Which statement is correct?
Junior
A.DML — a stored named query that presents data as a virtual table without physically storing it
B.DML — a join returning all rows from both tables, filling nulls where there is no match
C.DML — the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT
D.DML — the SQL category for manipulating data with commands like INSERT, UPDATE and DELETE
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7. What is DCL?
Mid
A.a join returning only the rows that have matching values in both tables
B.a set operator combining two query results while keeping all duplicate rows
C.a fast DDL operation that removes all rows of a table without logging each row deletion
D.the SQL category for access control with GRANT and REVOKE commands
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8. Which term means: "the SQL category for access control with GRANT and REVOKE commands"?
Mid
A.Full outer join
B.TCL
C.Self join
D.DCL
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9. Which statement is correct?
Mid
A.DCL — the SQL category for access control with GRANT and REVOKE commands
B.DCL — a clause that collapses rows sharing a value into summary groups for aggregation
C.DCL — a set operator combining two query results and removing duplicate rows
D.DCL — a fast DDL operation that removes all rows of a table without logging each row deletion
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10. What is TCL?
Mid
A.a join returning all rows of the left table plus matching right rows, nulls where none match
B.the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT
C.a clause that filters groups after aggregation, unlike WHERE which filters rows
D.a subquery that references the outer query and re-executes for each outer row
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11. Which term means: "the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT"?
Mid
A.Full outer join
B.DELETE command
C.UNION ALL operator
D.TCL
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12. Which statement is correct?
Mid
A.TCL — the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT
B.TCL — the SQL category for access control with GRANT and REVOKE commands
C.TCL — a join producing the Cartesian product of every row in one table with every row in another
D.TCL — a fast DDL operation that removes all rows of a table without logging each row deletion
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13. What is Inner join?
Junior
A.a join returning only the rows that have matching values in both tables
B.a join producing the Cartesian product of every row in one table with every row in another
C.a set operator combining two query results and removing duplicate rows
D.the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT
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14. Which term means: "a join returning only the rows that have matching values in both tables"?
Junior
A.Inner join
B.View
C.DCL
D.Cross join
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15. Which statement is correct?
Junior
A.Inner join — a join returning all rows of the left table plus matching right rows, nulls where none match
B.Inner join — a DML operation that removes selected rows and can be rolled back
C.Inner join — the SQL category for defining schema with commands like CREATE, ALTER and DROP
D.Inner join — a join returning only the rows that have matching values in both tables
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16. What is Left outer join?
Mid
A.a set operator combining two query results and removing duplicate rows
B.the SQL category for defining schema with commands like CREATE, ALTER and DROP
C.a join returning all rows of the left table plus matching right rows, nulls where none match
D.a clause that filters groups after aggregation, unlike WHERE which filters rows
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17. Which term means: "a join returning all rows of the left table plus matching right rows, nulls where none match"?
Mid
A.DCL
B.Left outer join
C.WHERE clause
D.TCL
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18. Which statement is correct?
Mid
A.Left outer join — a clause that filters groups after aggregation, unlike WHERE which filters rows
B.Left outer join — a join producing the Cartesian product of every row in one table with every row in another
C.Left outer join — a set operator combining two query results while keeping all duplicate rows
D.Left outer join — a join returning all rows of the left table plus matching right rows, nulls where none match
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19. What is Full outer join?
Mid
A.a join returning all rows from both tables, filling nulls where there is no match
B.a stored named query that presents data as a virtual table without physically storing it
C.a join returning only the rows that have matching values in both tables
D.the SQL category for access control with GRANT and REVOKE commands
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20. Which term means: "a join returning all rows from both tables, filling nulls where there is no match"?
Mid
A.TRUNCATE command
B.Full outer join
C.View
D.DDL
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21. Which statement is correct?
Mid
A.Full outer join — a set operator combining two query results while keeping all duplicate rows
B.Full outer join — a join returning all rows of the left table plus matching right rows, nulls where none match
C.Full outer join — a clause that filters groups after aggregation, unlike WHERE which filters rows
D.Full outer join — a join returning all rows from both tables, filling nulls where there is no match
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22. What is Cross join?
Mid
A.a clause that collapses rows sharing a value into summary groups for aggregation
B.a subquery that references the outer query and re-executes for each outer row
C.a set operator combining two query results and removing duplicate rows
D.a join producing the Cartesian product of every row in one table with every row in another
Answer + AI explanation with a free account
23. Which term means: "a join producing the Cartesian product of every row in one table with every row in another"?
Mid
A.HAVING clause
B.DML
C.Left outer join
D.Cross join
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24. Which statement is correct?
Mid
A.Cross join — a clause that filters groups after aggregation, unlike WHERE which filters rows
B.Cross join — a subquery that references the outer query and re-executes for each outer row
C.Cross join — a join producing the Cartesian product of every row in one table with every row in another
D.Cross join — the SQL category for defining schema with commands like CREATE, ALTER and DROP
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25. What is Self join?
Mid
A.a stored named query that presents data as a virtual table without physically storing it
B.a join in which a table is joined to itself to relate its own rows
C.a set operator combining two query results and removing duplicate rows
D.a clause that filters groups after aggregation, unlike WHERE which filters rows
Answer + AI explanation with a free account
26. Which term means: "a join in which a table is joined to itself to relate its own rows"?
Mid
A.Self join
B.HAVING clause
C.Correlated subquery
D.WHERE clause
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27. Which statement is correct?
Mid
A.Self join — a join in which a table is joined to itself to relate its own rows
B.Self join — a join returning all rows from both tables, filling nulls where there is no match
C.Self join — a clause that filters groups after aggregation, unlike WHERE which filters rows
D.Self join — the SQL category for access control with GRANT and REVOKE commands
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28. What is WHERE clause?
Junior
A.a join in which a table is joined to itself to relate its own rows
B.a clause that filters individual rows before any grouping is applied
C.a clause that collapses rows sharing a value into summary groups for aggregation
D.a set operator combining two query results while keeping all duplicate rows
Answer + AI explanation with a free account
29. Which term means: "a clause that filters individual rows before any grouping is applied"?
Junior
A.WHERE clause
B.DDL
C.GROUP BY clause
D.DML
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30. Which statement is correct?
Junior
A.WHERE clause — a join in which a table is joined to itself to relate its own rows
B.WHERE clause — a clause that filters individual rows before any grouping is applied
C.WHERE clause — the SQL category for managing transactions with COMMIT, ROLLBACK and SAVEPOINT
D.WHERE clause — the SQL category for manipulating data with commands like INSERT, UPDATE and DELETE
Answer + AI explanation with a free account
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