查询选修课程号为''101''并且成绩高于学生号为''9501101''的所有学生的成绩

select * from sclass 
 where cno=''101'' and degree>=

(select degree from sclass where sno=''9501101''and cno=''101'')

给出人口多于俄国的国家名称

SELECT NAME FROM BBC 
WHERE POPULATION>
(SELECT POPULATION FROM BBC WHERE NAME='RUSSIA')

给出人均GDP超过英国的欧洲国家

SELECT NAME FROM BBC
WHERE REGION ='EUROPE'  AND GDP/POPULATION>
(SELECT GDP/POPULATION FROM BBC WHERE NAME='UNITED KINGDOM')