# Greenplum Database Reference Guide 

Reference information for Greenplum Database systems including SQL commands, system catalogs, environment variables, server configuration parameters, character set support, datatypes, and Greenplum Database extensions.

-   **[SQL Commands](sql_commands/sql_ref.html)**  

-   **[Data Types](data_types.html)**  

-   **[Summary of Built-in Functions](function-summary.html)**  

-   **[Additional Supplied Modules](modules/intro.html)**  

-   **[Character Set Support](character_sets.html)**  

-   **[Server Configuration Parameters](config_params/guc_config.html)**  

-   **[Database Utilities](../utility_guide/utility_guide.html)**

-   **[System Catalogs](system_catalogs/catalog_ref.html)**  

-   **[The gp\_toolkit Administrative Schema](gp_toolkit.html)**  

-   **[Server Programmatic Interfaces](extensions/srvapi_intro.html)**  

-   **[SQL Features, Reserved and Key Words, and Compliance](misc.html)**  


