Mysql 如何将sql中AVG函数的小数位数限制为2？

我想把平均数的小数点限制在2

SELECT grade.GStudNo, AVG(grade.Grade) AS Average, students.LName, students.FName, students.MName, students.Course
FROM students INNER JOIN grade ON students.StudNo = grade.GStudNo
WHERE GSem = '$sem' AND GYear = '$year'
GROUP BY grade.GStudNo
ORDER BY Average ASC LIMIT 3

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使用

ROUND

函数包装平均值计算

SELECT grade.GStudNo, ROUND( AVG(grade.Grade),2 ) AS Average, students.LName, students.FName, students.MName, students.Course
FROM students INNER JOIN grade ON students.StudNo = grade.GStudNo
WHERE GSem = '$sem' AND GYear = '$year'
GROUP BY grade.GStudNo
ORDER BY Average ASC LIMIT 3

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将它四舍五入到两个位置。

也许您正在寻找这个：

SELECT grade.GStudNo, CAST(AVG(grade.Grade) AS DECIMAL(10,2)) AS Average, students.LName, students.FName, students.MName, students.Course
FROM students INNER JOIN grade ON students.StudNo = grade.GStudNo
WHERE GSem = '$sem' AND GYear = '$year'
GROUP BY grade.GStudNo
ORDER BY Average ASC LIMIT 3

这只能得到2个小数

CAST(AVG(grade.Grade) AS DECIMAL(10,2))