Administration

SQL Information schema and catalogs

Query metadata views to inspect tables, columns and constraints.

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

SELECT ... FROM information_schema.tables / columns;

Examples

Query metadata views to inspect tables, columns and constraints.

SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';

SQLite-oriented example; consult the relevant dialect manual.

SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';

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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