要求如下：
The average performance rating (with descriptor associated to the rounded value) by department and sorted lowest to highest.
然后有两个Table，一个Table里包括Performance rating，department的信息，另一个表格是Performance rate以及对应的descriptor。想问一下SQL语句怎么写才对？
我自己写的是
Select Performance_rating, department, descriptor
From Table1
INNER Join Table2
On Table1.Performance_rating = Table2.Performance_rate
Order By Department
但是运行了报错说需要Department有aggregate_function
想问一下怎么解决，谢谢。

Select Performance_rating, department, descriptor
From Table1
INNER Join Table2
On Table1.Performance_rating = Table2.Performance_rate
Order By Department
目测没错啊，除非你存在 count，max，min，avg，sum 等否则都没聚合函数。