Administration

SQL EXPLAIN

Show a query execution plan; output and options differ by engine.

Availability: Common SQL with references for SQL standard, MySQL/MariaDB, PostgreSQL, SQL Server, SQLite and Oracle Database; syntax and feature support vary by engine and version.中文

Syntax

EXPLAIN [options] query;

Examples

Example (standard-style syntax). Verify supported keywords in your database.

EXPLAIN SELECT id FROM orders WHERE customer_id = 12;

SQLite-oriented variant; dialect behaviour may differ.

EXPLAIN QUERY PLAN SELECT id FROM orders WHERE customer_id = 12;

Parameters, options and clauses

Option / clause	Description
`EXPLAIN`	Show the optimizer's planned execution strategy.
`ANALYZE`	Some engines execute the statement and report actual statistics; this can run the query.
`FORMAT`	Choose plan output format where supported.
`Catalog / information schema`	Inspect objects and definitions through system metadata.
`Dialect / version`	Check the linked database manual for vendor-specific behaviour.

Dialect references

Safety note

Review a command and its target before running it. Commands that alter files, services, accounts, disks, permissions or databases may be difficult to reverse. Test in a safe environment and keep backups.

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