oracle---select语句

oracle的select语句例句

set lines 300;

select * from employees；

select first_name from employees；

select first_name,last_name from employees；

select first_name name from employees；

select first_name||last_name from employees；

select first_name||‘--->’||last_name from employees；

select first_name||q‘['s job is a ]'||job_id from employees；

select last_name,salary from employees where salary >= 3000；

select last_name,job_id,salary from employees where job_id =‘SA_REP’；

select last_name,job_id,salary from employees where job_id like‘SA_REP'；

select last_name,job_id,salary from employees where last_name like ‘_a%'；

select last_name,job_id,salary from employees where job_id like ‘SA\_%' escape ‘\’；

select last_name,job_id,salary from employees where job_id like‘SA_%' and salary > 3000;

select last_name,salary 300 from employees;

select last_name,12*salary 300 from employees;

select last_name,12*(salary 300) from employees;

select last_name,job_id,department_id,salary from employees order by 4;

select last_name,job_id,department_id,12*salary years from employees order by last_name,years;

select last_name,salary from employees order by last_name,salary desc nulls last;

select last_name,&column_name from employees where &conditions order by &sort；

select last_name,&&column_name from employees order by &column_name

========

set define employee_num = 123

select employee_id,last_name,salary from employees where employee_id = employee_num;

undefine employee_num = 123

========

set verify on(/off)

select last_name,&&column_name from employees order by &column_name

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功能篇

select * from tab where tabtype = ‘TABLE' ；查看当前用户下的表

select count(*) from employees；查询表中记录的行数

set linesize 200 设置一行显示200个字符

set pagesize 20 设置每页显示20行