-441 INVALID USE OF 'DISTINCT' OR 'ALL' WITH FUNCTION `function-name`

Explanation
  This error can occur
for the following situations:
 The keyword DISTINCT or ALL was detected within parentheses in
a reference to function function-name and the function
has been resolved as a scalar function. Use of the keywords DISTINCT
or ALL with the specified scalar function is invalid.
The keyword DISTINCT was detected within parentheses in a reference
to function function-name and the function has
been resolved as an aggregate function. Use of the keywords DISTINCT
with the specified aggregate function is not valid.
The function was expected to be an aggregate function supporting
the keyword ALL or DISTINCT, but the function that was resolved to
is not an aggregate function.

System action
  The statement cannot be processed.

Programmer response
  Take the appropriate action: If a scalar function is being used, then remove the keyword DISTINCT
or ALL.
If the function is an aggregate function that does not support
the DISTINCT or ALL keywords, then remove the keyword.
Otherwise, if an aggregate function is being used, then there
is a problem with function resolution. Check your SQL path to see
if the function is in one of the schemas, and also check the SYSIBM.SYSROUTINES
catalog for the spelling of the function name and the number and types
of parameters

SQLSTATE
  42601

-441 INVALID USE OF 'DISTINCT' OR 'ALL' WITH FUNCTION function-name

Explanation

System action

Programmer response

SQLSTATE

-441 INVALID USE OF 'DISTINCT' OR 'ALL' WITH FUNCTION `function-name`