Answer:

Optimizing a database query is essential for improving application performance. If a query is taking a long time to execute, here are some steps to optimize it:

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  Identify the problem: First and foremost, we need to identify the problem by checking the query execution plan and analyzing the query statistics. This will help in finding the bottleneck and identifying the areas of improvement.
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  Reduce queries: Too many queries can slow down the application. We can reduce the number of queries by combining queries, eliminating redundant queries and avoiding unnecessary data retrieval.
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  Indexing: Proper indexing can significantly improve the performance of a database query. We can create indexes on columns that are frequently used in the queries.
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  Use the correct data types: We should use the correct data types for table columns as it can have a significant impact on query performance. Choosing smaller data types will help to reduce I/O operations and hence can optimize the queries.
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  Use efficient syntax: The way we write a query can also affect performance. We should optimize the query syntax and avoid using complex statements.
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  Testing: Finally, testing the optimized query and comparing the execution time can help in determining whether the optimizations are successful or not.

By implementing these steps, we can optimize the database query and improve the application's performance.

Relevant citations:

• Oracle:
  Top 10 Performance Tuning Tips for Oracle Database
• SQLShack:
  20 database optimization tips for SQL Server developers
• Dataquest:
  10 Tips for Optimizing MySQL Queries That Don’t Suck