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在學(xué)校php過程中，需要用得到的一些語句。比較簡單的大家一定要掌握
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;
||連接符使用以及 加減乘除以及括號(hào)的使用
SQL> select employee_id,first_name||’.’||last_name,salary*(1+0.1)/100,manager_id
2 from employees;
+-做正負(fù)號(hào)使用
SQL> select -salary from employees;
,>,SQL> select * from employees where salary >13000;
SQL> select * from employees where salary 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(比任意一個(gè)都)
select * from employees where employee_id >any(100,101,102);
some 是 SQL-92 標(biāo)準(zhǔn)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;
邏輯操作符
And 和 or
select * from employees where employee_id > 100 and employee_id select * from employees where employee_id > 100 or employee_id 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啞元表沒有表需要查詢的時(shí)候可以用它
select sysdate from dual;
select 1*2*3*4*5 from dual;
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