1.select count(*) from employees where last_name like _A%;key:02.select count(*)from employeeswhere to_char(hire_date,YYYY)=1998;select count(*)from employeeswhere hire_date like %98;key:23select to_char(hire_date,YYYY) from employees;3.se
1.
select count(*) from employees
where last_name like '_A%';
key:0
2.
select count(*)
from employees
where to_char(hire_date,'YYYY')=1998;
select count(*)
from employees
where hire_date like '%98';
key:23
select to_char(hire_date,'YYYY') from employees;
3.
select job_title, max_salary-min_salary as "SAL_DIEF"
from jobs
order by max_salary-min_salary desc;
select job_title,(max_salary-min_salary) as "SAL_DIEF"
from jobs
order by 2 desc;
19行记录
4.
select count(*)
from employees
where (salary>12000 or salary12000;
--当它判断1000为假时就不判断后面的大于12000了.
select job_id from employees;
select * from employees
where job_id in('ST_MAN','SH_CLERK');
--工作岗位名称要加单引号
5.
select count(*)
from employees
where to_char(hire_date,'YYYY')=1999
and to_char(hire_date,'mm')=02;
key:3
select count(*)
from employees
where to_char(hire_date,'YYYY-MM')='1999-02';
6.
select last_name,salary,
decode(trunc(salary/1500),0,'A',
1,'B',
2,'C',
'D'
) Grade
from employees
where last_name like'%s';
7.
select d.department_id,d.department_name,l.city
from departments d,locations l
where d.department_id in(10,40,90)
and d.location_id=l.location_id;
8.
select l.city,c.country_name,r.region_name
from locations l,regions r,countries c
where l.location_id=1000
and l.country_id=c.country_id
and c.region_id=r.region_id;
9.
select m.last_name "MAN_NAME",nvl(e.last_name,'NO EMPLOYEES') "EMP_NAME"
from employees m,employees e
where m.department_id=100
and m.employee_id=e.manager_id(+);
10行记录
select m.last_name MAN_NAME,nvl(e.last_name,'NO EMPLOYEES') EMP_NAME
from employees m,employees e
where m.department_id=100
and m.employee_id=e.manager_id(+);
10
select department_id,count(*) NUM
from employees
where salary>8000
group by department_id
;
9行记录
11
select department_id,count(*) NUM
from employees
where salary>5000
group by department_id
having count(*)>3;
3行记录
12
select last_name,salary
from employees
where salary>
(select salary from employees where employee_id=110)
and department_id=100;
2行记录
13
select count(*) NUM
from employees
where commission_pct<all distinct commission_pct from employees where salary>12000
and commission_pct is not null
);
24行记录
</all>
