How do I use the EXPLAIN statement in SQL?

How do I use the EXPLAIN statement in SQL?

The EXPLAIN statement in SQL is used to obtain information about how SQL queries are executed. It provides details on the execution plan, including which indexes are used and the order of operations.

Can you give me an example of how to use it?

Sure! For example, you can run EXPLAIN SELECT * FROM employees WHERE department = 'Sales'; This will show you how the database plans to execute that query.

What kind of output should I expect from that?

You will see a table with columns like id, select_type, table, type, possible_keys, and key. Each row represents a step in the query execution.

How can I interpret the output?

You can look at the type column to understand the join type used, and the key column to see which index was utilized. Lower values in the type column generally indicate better performance.