Boost Query Performance with Effective Indexing

Using Indexes to Improve Query Performance

Write a SQL query to create an index on a frequently queried column.

Solution:

-- Create an index on the "LastName" column in the Employees table.
CREATE INDEX IX_Employees_LastName
ON Employees (LastName);

Explanation:

• Purpose of the Query :
• The goal is to improve query performance by creating an index on a frequently searched column.
• Key Components :
• CREATE INDEX: Creates an index to speed up searches.
• IX_Employees_LastName: A meaningful name for the index.
• Why Use Indexes? :
• Indexes allow the database engine to quickly locate rows, reducing query execution time.
• They are particularly useful for large tables with frequent read operations.
• Real-World Application :
• In customer databases, indexing columns like "LastName" or "Email" speeds up search operations.

Notes:

• Over-indexing can degrade write performance (INSERT, UPDATE, DELETE).
• Regularly monitor and maintain indexes to ensure they remain effective.
• Important Considerations:
• Avoid indexing columns with low selectivity (e.g., boolean flags).

For more Practice: Solve these Related Problems:

• Write a SQL query to create an index on the "Email" column in the Users table to speed up login queries.
• Write a SQL query to create a composite index on the "FirstName" and "LastName" columns in the Employees table for faster search operations.
• Write a SQL query to create an index on the "OrderDate" column in the Orders table to optimize date-based filtering.
• Write a SQL query to create a unique index on the "ProductCode" column in the Products table to enforce uniqueness and improve search performance.

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