Select * from tablename SQL select * from employees; Select select list from tablename SQL select employee_id,first_name from employees; Select distinct … from tablename SQL select distinct manager_id from employees; ||连接符使用以及
Select * from tablename SQL> select * from employees; Select select list from tablename SQL> select employee_id,first_name from employees; Select distinct … from tablename SQL> select distinct manager_id from employees; ||连接符使用以及 加减乘除以及括号的使用 SQL> select employee_id,first_name||'.'||last_name,salary*(1+0.1)/100,manager_id 2 from employees; +-做正负号使用 SQL> select -salary from employees; <>,>,<,=,!=等比较操作符 SQL> select * from employees where salary >13000; SQL> select * from employees where salary <13000; SQL> select * from employees where salary <>13000; SQL> select * from employees where salary =13000; In SQL> select -salary from employees where employee_id in (100,101,102); SQL> select -salary from employees where employee_id in (select employee_id from employees); not in SQL> select -salary from employees where employee_id not in (100,101,102); Any(比任意一个都) select * from employees where employee_id >any(100,101,102); some 是 SQL-92 标准的 any 的等效物 select * from employees where employee_id >any(100,101,102); all（比所有的都） select * from employees where employee_id >all(100,101,102); between and select * from employees where employee_id between 100 and 102; not between and select * from employees where employee_id not between 100 and 102; 逻辑操作符 And 和 or select * from employees where employee_id > 100 and employee_id < 1000; select * from employees where employee_id > 100 or employee_id < 1000; Order by Desc select * from employees where employee_id between 100 and 102 order by employee_id desc; Asc select * from employees where employee_id between 100 and 102 order by employee_id asc; dual哑元表没有表需要查询的时候可以用它 select sysdate from dual; select 1*2*3*4*5 from dual;
