The SQL language standard has grown from a modest SQL'92 document of less then a 100 pages to the latest SQL:2008 >4000 page description comprised of the following volumes:
ISO/IEC 9075-1 Framework (SQL/Framework)
ISO/IEC 9075-2 Foundation (SQL/Foundation)
ISO/IEC 9075-3 Call Level Interface (SQL/CLI)
ISO/IEC 9075-4 Persistent Stored Modules (SQL/PSM)
ISO/IEC 9075-9 Management of External Data (SQL/MED)
ISO/IEC 9075-10 Object Language Bindings (SQL/OLB)
ISO/IEC 9075-11 Information and Definition Schemas (SQL/Schemata)
ISO/IEC 9075-13 Routines and Types using the Java Language (SQL/JRT)
ISO/IEC 9075-14 XML-related specifications (SQL/XML)
The MonetDB SQL implementation is based on SQL 2003 with a limited extension to features found elsewhere. The tables below illustrates the (un) supported features in the current distribution. Beware, some of the features are technically impossible to support due to the design of MonetDB or would cause excessive performance consequences.
Migration from your favored database system may require adjustment of the schema and query formulation. A comparison table for most actively used features is given in the SQL compatibility wikibook.