mysql - 添加列的 Group_concat

Question

我得到了一个运行良好的查询:

SELECT Course, Period, Room, Location, TeacherId, GROUP_CONCAT(StudentId) as Students 
FROM cursosv2 
GROUP BY Course, Period, Room, Location, TeacherID;

我想要的(也许太基本了)是在结果查询中拥有一个新列，例如带有 period+room+'final' 联接值的 NEW COLUMN A。但我不断遇到异常(exception)。不知道真正的原因。

我在尝试什么...

SELECT Course, Period, Room, Period+' '+Room+' Final' as test, Location, TeacherId, GROUP_CONCAT(StudentId) as Students 
FROM cursosv2 
GROUP BY Course, Period, Room, Location, TeacherID;

谢谢。

Answer 1

您还应该使用 concat 进行字符串连接(而不是 + )并添加到分组依据

 SELECT Course, Period, Room, concat( Period,' ',Room,' Final') as test, Location, TeacherId, GROUP_CONCAT(StudentId) as Students 

 FROM cursosv2 
 GROUP BY Course, Period, test, Room, Location, TeacherID;