语法错误：缺少`右括号`MySQL

Question

  

我不知道如何在此处收到此错误消息：

以下是查询：

SELECT t1.*,t2.totalAvg, ABS(`average for this subject`-totalAvg)  AS Difference, 100*MIN(`average for this subject`,totalAvg)/MAX(`average for this subject`,totalAvg) AS precent
FROM (SELECT StudentFirstName,StudentLastName,ClassName,AVG(Grade) AS `average for this subject`
      FROM tests
      INNER JOIN students ON tests.StudentID=students.StudentID
      GROUP BY StudentFirstName,StudentLastName,ClassName
     ) t1
JOIN (SELECT StudentFirstName,StudentLastName,AVG(`average for this subject`) as totalAvg
      FROM (SELECT StudentFirstName,StudentLastName,ClassName,AVG(Grade) AS `average for this subject`
            FROM tests
            INNER JOIN students ON tests.StudentID=students.StudentID
            GROUP BY StudentFirstName,StudentLastName,ClassName
           ) t
      GROUP BY StudentFirstName,StudentLastName
     ) t2 
ON t1.StudentFirstName=t2.StudentFirstName and t1.StudentLastName=t2.StudentLastName

Answer 1

您的代码可能有其他错误，但这在MySQL中肯定是错误的：

MIN(`average for this subject`, totalAvg)

MIN()只接受一个参数。据推测，您需要LEAST()：

LEAST(`average for this subject`, totalAvg)