Abstract: Disclosed herein are system, method, and computer program product embodiments for converting queries and scripts used in big data systems. A script conversion system converts a script and its queries from a first big data format to a second big data format. The script conversion system uses a configuration mapping that includes direct and/or indirect function mappings. For the direct mapping, the script conversion system replaces the function with a new function in the second big data format. For the indirect mapping, the script conversion system constructs an equivalent function in the second big data format using information extracted from parsing queries in the first big data format. The script conversion system also formats a converted query using a project mapping and/or generates a conversion report indicating successful or unsuccessful conversions. Scripts may be converted from an on-premises data warehouse system to a cloud-based data warehouse system.