Oracle常用命令（no 3）

語法

select  *|

from table
[where condition(s)];

示例

select last_name, job_id, department_id

from employees
where last_name = 'whalen';

等於（不是==）

>

大於>=大於、等於

<

小於<=

小於、等於

<>

不等於（也可以是！=）

示例

select last_name, salary

from employees
where salary <= 3000;

含義between…and…

在兩個值之間（包含邊界）

in(set)

等於值列表中的乙個

like

模糊查詢

is null空值

between

select last_name, salary

from employees
where salary between 2500
and3500;

select employee_id, last_name, salary, manager_id

from employees
where manager_id in (100, 101, 201);

select  first_name

from employees
where first_name like
's%';

select last_name

from employees
where last_name like
'_o%';

迴避特殊符號的：使用轉義符。例如：將[%]轉為[\%]、[_]轉為[\_]，然後再加上[escape 『\』] 即可

select job_id

from jobs
where job_id like 『it\_%『 escape 『\『;

select last_name, manager_id

from employees
where manager_id is
null;

含義and

邏輯並or

邏輯或not

邏輯否

and

select employee_id, last_name, job_id, salary

from employees
where salary >=10000
and job_id like
'%man%';

select employee_id, last_name, job_id, salary

from employees
where salary >= 10000
or job_id like
'%man%';

select last_name, job_id

from employees
where job_id 
notin ('it_prog', 'st_clerk', 'sa_rep');

1算術運算子

2連線符

3比較符

4is[not]null,like,[not]in

5[not]between

6not

7and8or

可以使用括號改變優先順序順序

示例1

select   last_name, job_id, department_id, hire_date

from employees
order
by hire_date ;

select   last_name, job_id, department_id, hire_date

from employees
order
by hire_date desc ;

select employee_id, last_name, salary*12 annsal

from employees
order
by annsal;

select last_name, department_id, salary

from employees
order
by department_id, salary desc;

優先順序排序

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