当我需要计算一个百分比时，我简单地使用这个。

ROUND(CAST((Numerator * 100.0 / Denominator) AS FLOAT), 2) AS Percentage

请注意，100.0返回一个小数，而100本身将把结果四舍五入到最接近的整数，即使使用round(…，2)函数!

我已经测试了以下内容，这确实有效。戈迪伊的答案很接近，但在错误的位置上乘了100，并且缺少了一些括号。

Select Grade, (Count(Grade)* 100 / (Select Count(*) From MyTable)) as Score
From MyTable
Group By Grade

你可以在你的from查询中使用子选择(未经测试，不确定哪个更快):

SELECT Grade, COUNT(*) / TotalRows
FROM (SELECT Grade, COUNT(*) As TotalRows
      FROM myTable) Grades
GROUP BY Grade, TotalRows

Or

SELECT Grade, SUM(PartialCount)
FROM (SELECT Grade, 1/COUNT(*) AS PartialCount
      FROM myTable) Grades
GROUP BY Grade

Or

SELECT Grade, GradeCount / SUM(GradeCount)
FROM (SELECT Grade, COUNT(*) As GradeCount
      FROM myTable
      GROUP BY Grade) Grades

你也可以使用存储过程(Firebird语法不好意思):

SELECT COUNT(*)
FROM myTable
INTO :TotalCount;

FOR SELECT Grade, COUNT(*)
FROM myTable
GROUP BY Grade
INTO :Grade, :GradeCount
DO
BEGIN
    Percent = :GradeCount / :TotalCount;
    SUSPEND;
END

当我需要计算一个百分比时，我简单地使用这个。

ROUND(CAST((Numerator * 100.0 / Denominator) AS FLOAT), 2) AS Percentage

请注意，100.0返回一个小数，而100本身将把结果四舍五入到最接近的整数，即使使用round(…，2)函数!

在任何sql server版本中，您都可以使用一个变量来表示所有等级的总和，如下所示:

declare @countOfAll decimal(18, 4)
select @countOfAll = COUNT(*) from Grades

select
Grade,  COUNT(*) / @countOfAll * 100
from Grades
group by Grade

你们需要在成绩领域分组。这个查询应该为您提供在几乎任何数据库中要查找的内容。

    Select Grade, CountofGrade / sum(CountofGrade) *100 
    from
    (
    Select Grade, Count(*) as CountofGrade
    From Grades
    Group By Grade) as sub
    Group by Grade

您应该指定您正在使用的系统。