查找各个学科的成绩前3名的学生信息Sql,有2种方法,一种是利用sql的row_number() over()函数,另一种是用子查询, 表设计如下 如果不考虑各个学科的成绩有并列的情况的话,有如下两种方法进行查询, 1. ROW_NUMBER() OVER()函数 select * from (select ROW_NUMBER() OVER(partition by CourseName ORDER BY Score desc) AS rownum,* from MyTest) as awhe
创建表:Create table If Not Exists Employee (Id int, Name varchar(255), Salary int, DepartmentId int);Create table If Not Exists Department (Id int, Name varchar(255));Truncate table Employee;insert into Employee (Id, Name, Salary,DepartmentId) values ('
select sname from student where not exists (select * from course where not exists (select * from sc where sno =student.sno and cno=course.cno); 最内部的 select * from sc where sno=student.sno and cno = course.cno是查询出所有已经选择过课程的学生及相应课程,select * from cour
MYSQL可以使用如下的用法: SELECT id FROM partner_broker_account_record ORDER BY id LIMIT 2, 1 在limit为2的基础上加1, sql server是: select top 1 * from tbl_score where tbl_score NOT IN ( select top 2 * from tbl_score )
select convert(varchar(10),dateadd(dd,number,dateadd(month,-1,getdate())),120) as dtfrom master..spt_values where type='P' and dateadd(dd,number,dateadd(month,-1,getdate()))<=getdate()--------------------- 作者:a-b-d 来源:CSDN 原文:https://blog.csdn.net/a6
SQL查询记录中增加序列号 根据学生成绩在查询结果中增加排名字段: 1.SELECT ROW_NUMBER() OVER (ORDER BY SCORE ASC) AS RANK,NAME,SCORE FROM GRADE ORDER BY SCORE; 此写法是直接在结果记录添加顺序排序序号 2.SELECT RANK() OVER (ORDER BY SCORE ASC) AS RANK,NAME,SCORE FROM GRADE ORDER BY SCORE; 此写法的根据排序依据列的值进
一.SQL语言查询选修了全部课程的学生的学号和姓名. 两种解决途径: 第一种: 我们可以表示为在SC表中某个学生选修的课程数等于C表中课程总数.相应的SQL语言如下: select S#,SNAME from S where S# in (select S# from SC group by S# --根据Sno分组,统计每个学生选修了几门课程.如果等于C表课程的总数,就是我们要找的S# having count(*) = (select count(*) from C))--统计C表中共有几门
/* *录入N个学生的成绩,并求出这些学生的总成绩和平均成绩! * */ import java.util.Scanner; public class SumTest{ public static void main(String args[]){ int i = 0; int sum = 0; System.out.println("请输入总学生的数量:"); Scanner sc = new Scanner(System.in ); int n = sc.nextInt(); wh
一:字符串条件查询 //直接实例化Model $user=M('user1'); var_dump($user->where ('id=1 OR age=55')->select()); 最终生成的sql语句为:SELECT * FROM `user1` WHERE ( id=1 OR age=55 ) PS:where 查询方法里面只要包含条件即可,多个条件加上 AND 等连接符即可 二:使用索引数组作为查询条件 $user=M('user1'); $condition['age']='55
select * from emp; --1.找出部门30的员工select * from emp where deptno = 30; --2.列出所有办事员(CLERK)的姓名,变化和部门编号select * from emp where job = upper('clerk'); --3.找出佣金高于薪金的员工.select * from emp where comm > sal; --4.找出佣金高于薪金60%的员工.select * from emp where comm > sal
真不简单!! 一:使用select语句进行查询 语法: SELECT <列名> FROM <表名> [WHERE <查询条件表达式>] [ORDER BY <排序的列名>[ASC或DESC]] eg1: SELECT SCode,SName,SAddress FROM Students WHERE SSEX = 0 ORDER BY SCode 二:查询所有列和行: eg:
