数据库小面试题

1.查询学生总分排名前三的学生姓名：

 

SELECT score.`name` from score GROUP BY score.`name` HAVING SUM(score.score) in 

(SELECT * from (SELECT DISTINCT (SUM(score.score)) from score GROUP BY score.`name` order by SUM(score.score)  desc LIMIT 3) as t );

　2.varchar(512)升级到varchar(1024)后测试

varchar
mysql中varchar存储的中文字符、英文字符、数字，是一致的，varchar(512)能存储512和汉字或者数字或者字母；
sql server中varchar存储汉字不同，一个汉字占两个字符；
针对能存储的汉子和字母数字字符数，进行不同内容长度的测试；

 3.在成绩表里查询各科成绩都在80以上(含80分)的学生姓名

select * from score a where a.name not in (select distinct(b.name) from score b where b.score <80)