How to Optimise SQL Queries? Quick Tips

SQL is the language to interact with databases, so we need to make them as fast as possible as the Database Operations may usually be expensive.

Use indexes

Indices should be put on tables. A table should at least have a primary key as a primary index. Indices should be carefully added to improve the queries.

Consider creating indexes on columns used in your queries to improve query performance (especially those complex join statements).

Avoid large result sets

Try to limit the number of columns and rows returned by your queries. This will reduce the amount of data that needs to be transferred over the network, resulting in faster queries.

Split or Partition Data Set is a good way to reduce the size for a single Database or Table.

Cache frequently used data

Caching frequently used data can help reduce the amount of disk I/O required to retrieve data, leading to improved query performance.

We can add extra layers of caching to inner SQL statement to improve the query efficiency/performance.

Use prepared statements

Prepared statements can help minimize execution time and network traffic by caching query plans and avoiding re-parsing of SQL statements each time they are executed.

Avoid unnecessary joins

Join queries are expensive. Joins can be expensive operationally, so try to simplify your query structure by using sub-queries instead of joins when possible.

Use EXPLAIN QUERY PLAN

EXPLAIN QUERY PLAN is a useful tool for analyzing and optimizing SQL queries, as it provides detailed information about how a given query will be executed by the database engine, helping identify inefficient patterns in your queries that can be improved upon for better performance.

In MySQL, you can simply “explain” any sql statements to find out how the indices (if applicable) can be used to speed up the queries.

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