I had this strange problem of Aggregation of views fields not disabled even after it has been set to no in the Views UI. When I checked the query there was a “group by” for the fields still present even after disabling aggregration.
That was a little tricky and took some time to figure this out. This was due to setting different aggregation like SUM, MIN, MAX etc.. to various fields before I disabled aggregation. This setting for all fields in Views UI has to be reset to GROUP RESULTS TOGETHER setting and saved for aggregation to be disabled. After this has been done, aggregation was disabled.