group by fV.tier_id, f.form_template_id

如果你喜欢(我需要应用这个)同时通过两列分组，我刚刚看到了这一点:

SELECT CONCAT (col1, '_', col2) AS Group1 ... GROUP BY Group1

GROUP BY col1, col2, col3

group by fV.tier_id, f.form_template_id

举个简单的例子，我有一个计数器，需要总结站点上每个访问页面的唯一IP地址。基本上是按页面名分组，然后按IP分组。我用DISTINCT和GROUP BY的组合解决了它。

SELECT pagename, COUNT(DISTINCT ipaddress) AS visit_count FROM log_visitors GROUP BY pagename ORDER BY visit_count DESC;

GROUP BY CONCAT(col1, '_', col2)