SQL数据库几个题目,100分悬赏！高手请进！

1、 select eno， ename，age from emp where job_title=‘高级’ and gender=1

2、
∏eno， ename，age (φjob_title=‘高级’ and gender=1 (emp))
注:其中的∏表示投影,φ表示选择.

4、create index 索引名 on emp (eno)

5、select dept.dname ，count（emp .eno） from dept ，emp
where emp.dno=dept.dno
group by dename

6、select dept.dno ,dept.dname, avg(salary) from dept ，emp
where emp.dno=dept.dno and salary>3000
group by dename ,dno

1.select ENO,ENAME,AGE from EMP where JOB_TITLE='高级' and GENDER='1'
6.select DNO,DNAME, gongzi from EMP,(select DNO,AVG(SALARY)as gongzi from EMP group by DNO having AVG(SALARY)>3000 )as new where EMP.DNO=new.DNO