1、查詢平均分大於80分的學生的姓名
select name,avg(score) as sc from grade group by name having avg(score)>80;
2、查詢出所有科目都大於80分學生的姓名
select name from grade group by name having min(score)>80;
3、SQL求出分數都大於80的學生姓名及其總成績
select name,sum(score) as su from grade group by name having avg(score)>80;