text: SELECT * FROM
  (SELECT old_hash_value, SUM(${columnToSum}) AS "${sumColumnName}"
  FROM
  (
  SELECT old_hash_value, -${columnToSum} AS ${columnToSum}
  FROM stats$sql_summary s
  WHERE snap_id = ${beginSnap} AND s.module = '${moduleName}'
  UNION ALL
  SELECT old_hash_value, ${columnToSum} AS ${columnToSum}
  FROM stats$sql_summary s
  WHERE snap_id = ${endSnap} AND s.module = '${moduleName}' 
  ) c
  GROUP BY old_hash_value
  HAVING SUM(${columnToSum}) = 0
  ORDER BY 2 desc
  ) derived_table WHERE rownum <= ${maxRows}
  