MySQL数据库基础-2026-5-11-上五下两节课-索引

– 统计表中总数据量select count(*) from student;– 唯一索引查询student_no列有唯一索引select * from student where student_no ‘2025021027’;– 普通索引查询student_name列有普通索引select * from student where student_name ‘学生_21035’;– 无索引查询email列没有建立索引select * from student where email ‘student_21035qq.com’;– 主键索引查询id列是主键自带主键索引select * from student where id 9527;