Incorrect query results and problems with FULL GROUP BY

Question

I noticed that I was getting an invalid mapping of hostname_max and db_max after adding them to the query.

It appears that the GROUP BY is not properly grouping the data.

If I turn on FULL GROUP BY then I get an error message from MySQL.

Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'slow_query_log.dimension.sample' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by (1055)

该提问来源于开源项目：box/Anemometer

Answer 1

These two columns get added to the query

sql
  MAX(hostname_max) AS hostname_max,
  MAX(db_max) AS db_max,