Oracle JDBC Driver always returns zero for both “ResultSetMetaData.getScale()” and “ResultSetMetaData.getPrecision()” in case you use aggregate functions. Oracle support document 1587538.1 states that Precision and Scale are not available when using SQL functions and that this is expected behaviour, e.g.: if you create the following VIEW:

SQL> create view <VIEW NAME> as select max(<COLUMN NAME>) max_c1 from <TABLE NAME>;

…and then run a “DESCRIBE” on the VIEW:

SQL> desc <VIEW NAME>
 Name Null? Type
 ----------------------------------------- -------- ----------------------------
 MAX_C1 NUMBER

…you will notice that no Scale nor Precision has been packaged with the datum which in return means that JDBC also just returns the datatype given by the server. For 'normal' columns the data dictionary core catalogs are queried to obtain information like precision and scale . However, since for aggregate function the result of such functions do not exist in these catalogs, then they are unknown.

Oracle Document 1946626.1 delivers some details on how to interpret the precision and scale values