Currently, there is no more flexible approch for aggregate functions.
Scalar functions can be overloaded but aggregate functions do not
support this so far.
Regards,
Timo
Am 07.01.19 um 02:27 schrieb yinhua.dai:
Hi Timo,
But getResultType should only return a concrete type information, right?
How could I implement with a generic type?
I'd like to clarify my questions again.
Say I want to implement my own "MAX" function, but I want to apply it to
different types, e.g. integer, long, double etc, so I tried to write a class
which extends AggregateFunction *with generic type* to implement the max
function.
Then I want to register only one function name for all types.
E.g.
tableEnv.registerFunction("MYMAX", new MyMax());
instead of
tableEnv.registerFunction("MYINTEGERMAX", new MyIntegerMax());
tableEnv.registerFunction("MYLONGMAX", new MyLongMax());
tableEnv.registerFunction("MYDOULBEMAX", new MyDoubleMax());
Is there a way to implement that?
I know the build in function "MAX" can apply to all types, so I wonder if I
can also implement that.
Thanks.
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