mysql - 语法错误 : missing `closing parenthesis` MySQL

Question

I don't know way I got this error message here:

查询如下:

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

你的代码可能还有其他错误，但这在MySQL中肯定是不正确的:

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)