数据库，sql查询，mysql [英] database, sql query, mysql

问题描述

嗨 我有一张学生记录表，
我想计算特定年龄段的学生人数，并且还要增加年龄段.
输出将像
学生年龄
7 12
8 17
9 4
. .
. .
. .
28 21

解决方案

  SELECT 
    年龄，
    COUNT(StudentName) AS  [没有 名学生]
 FROM 
    TMP
组  BY 
    年龄
订单  BY 
    年龄

请根据您的表结构，用列名称替换年龄"和学生姓名".

你好，

如果你的结构像
表学生栏:StudentID(主键)，Name(varchar)，Firstname(varchar)，Dateofbirth(datetime)

然后用这个
SELECT FLOOR(DATEDIFF(day，Dateofbirth，GETDATE())/365.25)年龄，COUNT(*)AS [学生人数]来自TblEmployee GROUP BY FLOOR(DATEDIFF(day，Dateofbirth，GETDATE())/365.25);

希望它对您有用.

sanjeev

要计算指定年龄的学生人数，SQL查询为:

 选择 SUM(No_Of_Students)来自 [其中​​ Age = [您指定的年龄] 

计算指定年龄以下的学生人数:

 选择 SUM(No_Of_Students)来自 [位置(年龄= 1  OR 年龄= 3 ...  OR 年龄= [您指定的年龄] 

谢谢.

hi i have a table of students record,
i want to calculate number of students of a specific age , and also for increasing age.
the output will be like
Age No of students
7 12
8 17
9 4
. .
. .
. .
28 21


what will be the query for that, can anybody help e out?

解决方案

SELECT
    Age,
    COUNT(StudentName) AS [No of Students]
FROM
    TMP
GROUP BY
    Age
ORDER BY
    Age

Please replace "Age" and "StudentName" with the column name(s) as per your table structure.

hello ,

if your structure is like
TABLE STUDENTS COLUMNS: StudentID (primary key), Name(varchar), Firstname(varchar), Dateofbirth(datetime)

then use this
SELECT FLOOR(DATEDIFF(day,Dateofbirth , GETDATE()) / 365.25) AS AGE, COUNT(*) AS [No of Student] FROM TblEmployee GROUP BY FLOOR(DATEDIFF(day, Dateofbirth, GETDATE()) / 365.25);

hoping it will work for you.

sanjeev

For Calculating number of students of specified age the SQL Query is as :

Select SUM(No_Of_Students) From [table name] Where Age=[Your Specified Age]

And for Calculating number of students below the specified Age :

Select SUM(No_Of_Students) From [table Name] Where (Age=1 OR Age=2 OR Age=3 ... OR Age=[Your specified Age]

Thanks.

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