Since GreptimeDB's query engine is built based on Apache Arrow DataFusion, GreptimeDB inherits all built-in functions in DataFusion. These functions include:
Aggregate functions: such as COUNT(), SUM(), MIN(), MAX(), etc. For a detailed list, please refer to Aggregate Functions
Scalar functions: such as ABS(), COS(), FLOOR(), etc. For a detailed list, please refer to Scalar Functions
In summary, GreptimeDB supports all SQL aggregate functions and scalar functions in DataFusion. Users can safely use these rich built-in functions in GreptimeDB to manipulate and analyze data.