Question

我有这个查询工作得很好：

SELECT [Exam Category]
      ,[Student No_]
      ,Gender
      ,Description
      ,Stage 
FROM [MYDB $Course Registration]
    inner join [MYDB $Student] 
        ON [Student No_] = No_
    inner join [MYDB $Programme]
        ON Code = Programme
where Gender != 0
order by [Exam Category] desc
        ,[Student No_]
        ,Stage

但是，我想按[Exam Category]分组：

SELECT [Exam Category]
      ,[Student No_]
      ,Gender
      ,Description
      ,Stage 
FROM [MYDB $Course Registration]
    inner join [MYDB $Customer] 
        ON [Student No_] = No_
    inner join [MYDB $Programme]
        ON Code = Programme
where Gender != 0
group by [Exam Category]
order by  Stage
         ,[Student No_]

但它会带来错误

Msg 8120，Level 16，State 1，Line 9 专栏＃MYDB $课程注册。学生没有_＆＃39;在选择列表中无效，因为它不包含在聚合函数或GROUP BY子句中。

任何帮助？

Answer 1

注意 - 如果你通过选项给出group，那么*不能在select语句中你必须在select语句中提到列名 select列应具有max，count，sum等聚合函数，那些没有聚合函数名称的列应该在group by子句

之后指定那些列名

//在你的情况下，性别，描述，阶段不包括在分组中，

![SELECT [Exam Category]
  ,[Student No_]
  ,Gender
  ,Description
  ,Stage FROM [MYDB $Course Registration]
inner join [MYDB $Customer] 
    ON [Student No_] = No_
inner join [MYDB $Programme]
    ON Code = Programme where Gender != 0 group by [Exam Category]

我的代码参考检查

select MAX(Employee_Details.NewEmployeeId)
    ,Employee_Details.First_Name
from Employee_Details
INNER JOIN EmployeeDesignation_List ON Employee_Details.Designation=EmployeeDesignation_List.Designation_id
WHERE Employee_Details.Status='Active'
GROUP BY Employee_Details.First_Name
ORDER BY Employee_Details.First_Name

Answer 2

如果你想按Exam Category聚合，那么我希望这样的查询：

SELECT [Exam Category], COUNT(*)
FROM [MYDB $Course Registration] inner join
     [MYDB $Customer]
    ON [Student No_] = No_ inner join
    [MYDB $Programme]
    ON Code = Programme
where Gender <> 0
Group by [Exam Category];

请注意，所有其他列都已从SELECT中删除。

如果这不是您想要的，那么您应该编辑您的问题并提供样本数据和所需的结果。

在JOIN查询中使用GROUP BY SQL函数

2 个答案: