There are two types of Natural UDF:
scalar UDF
table UDF
The scalar UDF accepts several input arguments and returns one output value. It can be invoked by any SQL statement like a DB2 built-in-function.
The table UDF accepts several input arguments and returns a set of output values comprising one table row during each invocation.
You invoke a table UDF with a SELECT statement by specifying the table-function name in the FROM clause. A table UDF performs as a DB2 table and is invoked for each FETCH operation for the table-function specified in the SELECT statement.
