（1）SELECT * FROM C WHERE CNAME LIKE '%数据库%'（2）SELECT [S#]，SNAME FROM S a LEFT JOIN SC b ON [S#] = [S#] LEFT JOIN C ON [C#] = [C#] WHERE CNAME = 'MATHS'（3）SELECT [S#]，SNAME，SUM(CASE WHEN ISNULL(C#，'') = '' THEN 0 ELSE 1 END) AS [课程门数] FROM S a LEFT JOIN SC b ON [S#] = [S#]GROUP BY [S#]，SNAME（4）SELECT SNAME，AGE FROM S WHERE [S#] = '03240115'（5）SELECT GRADE FROM S a LEFT JOIN SC b ON [S#] = [S#] LEFT JOIN C ON [C#] = [C#] WHERE CNAME = '数据库原理' AND SNAME = '王芳'是不是要这样？
select ENO，ENAME，AGE from EMP where JOB_TITLE='高级' and GENDER='1'select DNO，DNAME， gongzi from EMP，(select DNO，AVG(SALARY)as gongzi from EMP group by DNO having AVG(SALARY)>3000 )as new where EMPDNO=DNO
