SQL Indexes MCQ Questions & Answers

This section focuses on the "Indexes" in SQL. These Multiple Choice Questions (MCQ) should be practiced to improve the SQL skills required for various interviews (campus interview, walk-in interview, company interview), placements and other competitive examinations.

1. An index helps to speed up?

A. SELECT queries
B. WHERE clauses
C. Both A and B
D. UPDATE Query

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2. What is true about index?

A. Indexes are special lookup tables that the database search engine can use to speed up data retrieval.
B. Indexes are special lookup tables that the database search engine can use to speed up data deletion.
C. Indexes can be created or dropped with an effect on the data.
D. An index helps to speed up insert statement.

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3. Which of the following is correct CREATE INDEX Command?

A. INSERT INDEX index_name ON table_name;
B. INSERT INDEX index_name ON database_name;
C. CREATE INDEX index_name ON database_name;
D. CREATE INDEX index_name ON table_name;

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4. A ______ index is created based on only one table column.

A. Implicit
B. Unique
C. single-column
D. Composite

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5. A _______ index is an index on two or more columns of a table.

A. Implicit
B. Unique
C. single-column
D. Composite

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6. Which of the following is correct DROP INDEX Command?

A. DROP INDEX table_name;
B. DROP INDEX index_name;
C. DROP INDEX index_name or table_name;
D. DELETE INDEX index_name;

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7. Can we use index on columns that contain a high number of NULL values?

A. YES
B. NO
C. Only Implicit Indexes can be used
D. Only Composite Indexes can be used.

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8. What is the syntax for UNIQUE Indexes?

A. CREATE INDEX index_name ON table_name (column_name);
B. CREATE UNIQUE INDEX index_name on table_name (column_name);
C. CREATE INDEX UNIQUE index_name on table_name (column_name);
D. CREATE INDEX index_name on UNIQUE table_name (column_name);

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9. How many types of indexes are there in sql server?

A. 1
B. 2
C. 3
D. 4

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10. If an index is _________________ the metadata and statistics continue to exists.

A. Dropping
B. Inserting
C. Altering
D. Disabling

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