c# - SQL 分组按月

Question

这是我的查询：

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

我想按月对约会日期列进行分组，如下所示：

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

但我的查询引发以下错误：

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

Answer 1

这会起作用吗：

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