Running a query with a correlated subquery in a HAVING clause, such as

SELECT INTKEY, STRINGKEY 
  FROM BQT1.SMALLA AS A 
  WHERE NOT (INTKEY IN (10)) 
  GROUP BY INTKEY, STRINGKEY 
  HAVING INTKEY = (SELECT MIN(STRINGKEY) FROM BQT1.SMALLA AS B WHERE A.INTKEY = B.INTKEY) 

fails on the datasource with

com.osisoft.rdsa.RdsaException: [PIOLEDBENT] HAVING condition cannot be nonaggregate.

This seems to be an issue on the Osisoft PI datasource side, as running the query directly against the datasource produces the same failure.