SQL group by month

Question

这是我的疑问：

SELECT COUNT(*) AS Expr1, name, appointment_date 
FROM ReportingTable 
GROUP BY name, appointment_date

我想按月将group_date列分组，如下所示：

SELECT COUNT(*) AS Expr1, name, appointment_date
FROM ReportingTable
GROUP BY name, MONTH(appointment_date)

但我的查询引发了以下错误：

  

列“appointment_date”在所选列表中无效，因为它   不包含在聚合函数或groupby子句中。

Answer 1

这会有效吗？

SELECT        COUNT(*) AS Expr1, name, MONTH(appointment_date) AS appointment_month
FROM            ReportingTable
GROUP BY name, appointment_month