What should be considered when optimizing SQL statement…

When optimizing SQL statements, there are some key points to keep in mind:

Index optimization: Ensure that there are appropriate indexes on key columns in the table, such as primary keys, foreign keys, and columns frequently used for searching and joining. The use of reasonable indexes can greatly improve query performance.

Avoid full table scans: Try to avoid executing queries on large tables without indexes or with inefficient indexes, as full table scans consume a lot of resources and can result in decreased performance. Make sure that query conditions utilize appropriate indexes to improve retrieval efficiency.

Optimize using JOIN: In multi-table queries, choose the appropriate JOIN type (such as INNER JOIN, LEFT JOIN, etc.) and ensure accurate connection conditions. You can also consider creating indexes for frequently used join columns.

Optimize subqueries by converting complex subqueries into more efficient JOIN operations to reduce the nesting levels and query time.

Avoid using SELECT *: Choose only the necessary columns instead of using SELECT *, as fetching only the required data can reduce network transmission overhead and additional IO burden.

Pagination optimization: For paginated queries, limit the result set size using the LIMIT statement to avoid retrieving too much data from the database.

Avoid inserting and updating data in single rows frequently: If there is a need for large-scale data insertion or update, consider using batch operations or more efficient methods like LOAD DATA.

Update database statistics: Ensure that the statistics for the database and tables are up to date in order to optimize query execution plans.

Regular monitoring and adjustment: Monitor the performance of the database and make adjustments as needed, such as adjusting parameter configurations, adding hardware resources, etc.

10. Choose the appropriate data type: selecting the right data type can reduce storage space, improve query efficiency, and avoid potential type conversion issues.

It is important to note that optimizing SQL statements is a complex process that involves considering multiple factors such as database structure, query requirements, hardware resources, and more. In some cases of intricate optimization needs, further analysis and optimization of the database architecture design may be required.