While using DB2390Dialect a call of the function getSelectClauseNullString in DB2Dialect returns "nullif(0,0)" in default case. The database returns the following error:
Error: DB2 SQL Error: SQLCODE=-170, SQLSTATE=42605, SQLERRMC=NULLIF, DRIVER=4.13.80
SQLState: 42605
ErrorCode: -170

The meaning of SQLCODE -170 is: THE NUMBER OF ARGUMENTS SPECIFIED FOR function-name IS INVALID

(0,0) isn't interpreted as two parameters.

The solution is to insert a trailing space after the comma. Inserting the space is syntactically correct in general. So this has no negativ impact on the other sqlTypes.