EXPLAIN

Performance

Shows the execution plan for a query, helping optimize performance.

Syntax

EXPLAIN [ANALYZE] SELECT ...

Example

EXPLAIN ANALYZE
SELECT u.name, COUNT(o.id)
FROM users u
JOIN orders o ON u.id = o.user_id
GROUP BY u.name;

About SQL EXPLAIN

The EXPLAIN keyword belongs to the Performance category of SQL statements. Shows the execution plan for a query, helping optimize performance. Understanding this command is essential for any developer working with relational databases like PostgreSQL, MySQL, SQLite, or SQL Server.

SQL (Structured Query Language) is the standard language for managing and querying relational databases. The EXPLAIN statement is supported across all major database systems, though specific syntax may vary slightly between PostgreSQL, MySQL, MariaDB, Oracle, SQL Server, and SQLite. Always consult your database's documentation for vendor-specific features and limitations.

Best practices for using EXPLAIN: always test queries on a development database before running them in production, use parameterized queries to prevent SQL injection, and leverage EXPLAIN to understand query performance. For complex queries, consider using CTEs (Common Table Expressions) to improve readability and maintainability.

Related SQL Keywords

CREATE INDEXSELECTJOINWHERE