Systems and apparatuses are provided for analytical data processing. A system includes a processor and a non-transitory computer readable medium, comprising machine readable instructions executable by the processor. The instructions include a query compiler to identify a call to a user defined function within a query. The call to a user defined function includes an input argument and a parameter expression defining a parameter value for the user defined function. A processing engine executes the user defined function to provide a function output according to the input argument and the defined parameter value.