Software Development Exam > Software Development Questions > Consider the following SQL query:SELECT name ...
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Consider the following SQL query:
SELECT name FROM employees WHERE age > 30;
Which of the following indexes would be most beneficial for optimizing this query?
SELECT name FROM employees WHERE age > 30;
Which of the following indexes would be most beneficial for optimizing this query?
- a)Index on the "name" column
- b)Index on the "age" column
- c)Composite index on both "name" and "age" columns
- d)No index is needed for this query
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
Consider the following SQL query:SELECT name FROM employees WHERE age ...
Since the query filters data based on the "age" column, creating an index on the "age" column would be most beneficial for optimizing the query.
Most Upvoted Answer
Consider the following SQL query:SELECT name FROM employees WHERE age ...
Index Optimization for SQL Query
Index on the "age" column:
- In the given SQL query, the condition is based on the "age" column, which is used in the WHERE clause to filter results where age is greater than 30.
- Creating an index on the "age" column will help the database engine quickly locate the rows that satisfy the condition without having to scan the entire table.
- This index will improve the query performance by reducing the number of rows that need to be scanned, especially in large tables with many records.
Index on the "name" column:
- Creating an index on the "name" column would not be as beneficial for optimizing this specific query because the query is filtering based on the "age" column, not the "name" column.
- An index on the "name" column would be more useful for queries that involve filtering, sorting, or searching based on the "name" column, but it would not directly optimize the given query.
Composite index on both "name" and "age" columns:
- While a composite index on both "name" and "age" columns may improve performance for queries that involve filtering or sorting based on both columns, it is not necessary for the given query.
- In this case, creating a composite index may even introduce overhead without significant benefits since the query is primarily filtering based on the "age" column.
No index is needed for this query:
- While it is possible to run the query without any index, adding an index on the "age" column can significantly improve the query performance, especially in scenarios with a large number of records.
- Therefore, creating an index on the "age" column is the most beneficial option for optimizing the given SQL query.
Index on the "age" column:
- In the given SQL query, the condition is based on the "age" column, which is used in the WHERE clause to filter results where age is greater than 30.
- Creating an index on the "age" column will help the database engine quickly locate the rows that satisfy the condition without having to scan the entire table.
- This index will improve the query performance by reducing the number of rows that need to be scanned, especially in large tables with many records.
Index on the "name" column:
- Creating an index on the "name" column would not be as beneficial for optimizing this specific query because the query is filtering based on the "age" column, not the "name" column.
- An index on the "name" column would be more useful for queries that involve filtering, sorting, or searching based on the "name" column, but it would not directly optimize the given query.
Composite index on both "name" and "age" columns:
- While a composite index on both "name" and "age" columns may improve performance for queries that involve filtering or sorting based on both columns, it is not necessary for the given query.
- In this case, creating a composite index may even introduce overhead without significant benefits since the query is primarily filtering based on the "age" column.
No index is needed for this query:
- While it is possible to run the query without any index, adding an index on the "age" column can significantly improve the query performance, especially in scenarios with a large number of records.
- Therefore, creating an index on the "age" column is the most beneficial option for optimizing the given SQL query.
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Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer?
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Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer? for Software Development 2025 is part of Software Development preparation. The Question and answers have been prepared according to the Software Development exam syllabus. Information about Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Software Development 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer?.
Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer? for Software Development 2025 is part of Software Development preparation. The Question and answers have been prepared according to the Software Development exam syllabus. Information about Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer? covers all topics & solutions for Software Development 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Consider the following SQL query:SELECT name FROM employees WHERE age > 30;Which of the following indexes would be most beneficial for optimizing this query?a)Index on the "name" columnb)Index on the "age" columnc)Composite index on both "name" and "age" columnsd)No index is needed for this queryCorrect answer is option 'B'. Can you explain this answer?.
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