All versions of PostgreSQL. Add an additional version-specific tag like [postgresql-13] if that context is relevant.
PostgreSQL is a powerful, open source ACID compliant MVCC database system with a proven architecture that has earned a strong reputation for standards-compliance, reliability, data integrity, and extensibility.
PostgreSQL runs on all major operating systems and supports most of the major features of SQL:2016 including foreign keys, transactions, and window functions, views and materialized views, triggers, and CTEs (including recursive CTEs).
PostgreSQL supports most of the standard SQL types including:
- ENUMs (enumerated types)
- JSON and binary JSON
- Range types
- Non-spatial geometric types (points, lines, line segments etc.)
- Network address types, including ip and mac types
- Binary large objects
- Domains (essentially data types with optional constraints)
- User-implemented types in C, which have produced an ecosystem of extensions
PostgreSQL supports multicolumn, unique, full, partial and functional indexes, and combinations thereof. Index types include B-tree, Hash, GiST, SP-GiST, GIN and BRIN.
PostgreSQL is released under the PostgreSQL License, a liberal Open Source license, similar to the BSD or MIT licenses.