SQL Standard Reference
Reference for SQL:2016/2023 standard features, conformance levels, and dialect differences.
Standard Evolution
The SQL standard is maintained by ISO/IEC, evolving from SQL-86 through SQL:2023. Each edition adds features: SQL:1999 added triggers, recursive queries, and OLAP functions. SQL:2003 added XML, window functions, and MERGE. SQL:2011 added temporal tables. SQL:2016 added JSON and row pattern matching. SQL:2023 added property graph queries (SQL/PGQ). No database fully implements the standard; each has dialect extensions and omissions. Feature packages (e.g., T612, F841) identify supported capabilities.
- SQL:2016
- JSON, row patterns
- SQL:2023
- Property graphs
- conformance
- No full impl
MATCH_RECOGNIZESQL/PGQdialects varyCore vs Optional Features
Core SQL (Entry, Transitional, Intermediate, Full) defines conformance levels. Most databases implement a custom subset plus proprietary extensions. Standard features include schemas, views, constraints, transactions, and CRUD. Optional features include recursive queries, window functions, JSON, XML, arrays, and sequences. Cross-database portability requires sticking to core features and avoiding dialect-specific syntax. ORMs abstract differences but may limit access to advanced features. Always check feature support for target databases.
- core
- Basic CRUD + constraints
- optional
- JSON, arrays, recursive
- portability
- Stick to core
widely supportedvaries by DBavoid dialects