摘要:
1.创建数据库、相关表,并插入数据create database homework;use homework; create table class_grade(gid int primary key auto_increment, gname char(16));create table clas 阅读全文
摘要:
查询各科成绩前三名的记录,不考虑并列的情况; select a.course_id as 课程ID, a.score as 成绩, count(a.course_id) as 排名 from score a left join score b on a.course_id=b.course_id a 阅读全文