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Optimizing Ordered Results Retrieval in MySQL with EXPLAIN


Analyze Query with ORDER BY and LIMIT using EXPLAIN

Write a MySQL query that uses EXPLAIN to analyze a query retrieving the top 5 highest order amounts from the Orders table.

Solution:

-- Use EXPLAIN to analyze the performance of an ORDER BY query with a LIMIT clause.
EXPLAIN SELECT * FROM Orders
ORDER BY TotalAmount DESC
LIMIT 5;

Explanation:

  • Purpose of the Query:
    • To examine how MySQL executes a query that sorts data and limits the output.
    • Useful for optimizing queries that involve ordering large datasets.
  • Key Components:
    • ORDER BY TotalAmount DESC : Sorts the records in descending order by order amount.
    • LIMIT 5 : Restricts the output to the top 5 records.
  • Real-World Application:
    • Common in dashboards or reports highlighting top-performing orders.

Notes:

  • An index on TotalAmount can speed up sorting operations.
  • Use EXPLAIN output to refine index strategy for ordered queries.

For more Practice: Solve these Related Problems:

  • Write a MySQL query that uses EXPLAIN to analyze a query retrieving the top 10 highest revenue products from the Sales table.
  • Write a MySQL query that uses EXPLAIN to analyze a query retrieving the top 5 most expensive projects from the Projects table.
  • Write a MySQL query that uses EXPLAIN to analyze a query retrieving the top 7 most active customers from the Customers table.
  • Write a MySQL query that uses EXPLAIN to analyze a query retrieving the top 3 most recent orders from the Orders table.

Go to:


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NEXT : Force Index usage in a JOIN Query with Index Hints.

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