SQL Query Optimization MCQ Performance Tuning Practice Questions

Direction: Choose the correct option

Why is query optimization important?

A. More indexes

B. Faster performance, less server load

C. Complex queries

D. More code

Direction: Choose the correct option

EXPLAIN SELECT * FROM employees WHERE salary > 50000;

What does EXPLAIN do?

A. Shows query execution plan

B. Validates syntax

C. Runs query

D. Creates index

Direction: Choose the correct option

Which query is better optimized?

A. SELECT * FROM orders WHERE YEAR(order_date) = 2023

B. B,Neither

C. A,Both are same

D. SELECT * FROM orders WHERE order_date BETWEEN '2023-01-01' AND '2023-12-31'

Direction: Choose the correct option

What are query optimization tips?

A. Avoid functions on indexed columns

B. Use indexes, avoid SELECT *

C. Use JOINs instead of subqueries

D. All of the above

Direction: Choose the correct option

SELECT * FROM orders WHERE YEAR(order_date) = 2023;

How can this be optimized?

A. Use different function

B. No improvement needed

C. Use range condition: order_date BETWEEN '2023-01-01' AND '2023-12-31'

D. Add index on YEAR(order_date)

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