1.至少两门成绩大于或等于90的姓名和课程数量
SELECT a.name,COUNT(a.name) FROM stu a,sourse b WHERE a.no=b.stuid AND b.s>=90 GROUP BY a.no HAVING COUNT(a.name)>1;
2.每门成绩都大于80的姓名
SELECT a.name FROM stu a,sourse b WHERE a.no=b.stuid GROUP BY a.no HAVING MIN(s)>80;
3.找出总分最高的学生的no,name,总分数
SELECT a.no,a.name,SUM(b.grade) FROM tab1 a,tab2 b WHERE a.no=b.no GROUP BY a.no ORDER BY SUM(b.geade) DESC LIMIT 1;
4.查询年龄最大的学生编号姓名生日
SELECT id,NAME,DATE FROM emp WHERE YEAR(CURDATE())-YEAR(DATE)= (SELECT MAX(YEAR(CURDATE())-YEAR(DATE)) FROM emp);
5.计算出每个人生日和入学日期分别是星期几,以及在当年中是第几天
SELECT NAME,DAYNAME(birthday), 1+DATEDIFF(birthday,CONCAT(YEAR(birthday),"-01-01")), DAYNAME(sday), 1+DATEDIFF(sday,CONCAT(YEAR(sday),"-01-01")) FROM stu;