Currently user-defined aggregate functions must have one parameter.
SqlAggFunction need new constructor to set paramTypes to allow user-defined aggregate function to have more than one parameter.
If a class(A) implement interface of AggregateFunction,that instance of class will be transformed to instance of SqlUserDefinedAggFunction by call toOp method in CalciteCatalogReader.
when construct the SqlUserDefinedAggFunction instance will set paramTypes to null for super class sqlFunction indirectly.
The problem is:
we will get SqlUserDefinedAggFunction paramTypes to sql validatefilte,but it will be filter nothing