您必须在要分组的SELECt中列出列名：
SELECT c.id, c.name, SUM(ABS(v.vote)) AS scoreFROM categories c,items i, votes v WHERe c.id = i.category_id AND i.id = v.voteable_id AND v.created_at > '#{1.week.ago}'GROUP BY c.id, c.nameORDER BY score DESC LIMIT 8;“不允许在SELECT子句中包括GROUP BY子句中未引用的列名。”
