1.过滤：
SELECT *|{[DISTINCT] column|expression [alias],...}
FROM table
[WHERE condition(s)];
2.字符：
SELECT last_name, job_id, department_id FROM employees WHERE last_name = ‘Whalen‘;
3.比较运算符：
BETWEEN ...AND...（在两个值之间 (包含边界)）
SELECT last_name, salary FROM employees WHERE salary BETWEEN 2500 AND 3500;
IN(set) （等于值列表中的一个）
SELECT employee_id, last_name, salary, manager_id FROM employees WHERE manager_id IN (100, 101, 201);
LIKE（模糊查询）
SELECT first_name FROM employees WHERE first_name LIKE ‘S%‘;
IS NULL（空值）
SELECT last_name, manager_id
FROM employees
WHERE manager_id IS NULL;
4.逻辑运算：
AND（逻辑并）
SELECT employee_id, last_name, job_id, salary FROM employees WHERE salary >=10000 AND job_id LIKE ‘%MAN%‘;
OR（逻辑或）
SELECT employee_id, last_name, job_id, salary FROM employees WHERE salary >= 10000 OR job_id LIKE ‘%MAN%‘;
NOT（逻辑否）
SELECT last_name, job_id FROM emp WHERE job_id NOT IN (‘IT_PROG‘, ‘ST_CLERK‘, ‘SA_REP‘);
5.ORDER BY子句
使用 ORDER BY 子句排序 。
ASC: 升序
SELECT last_name, job_id, department_id, hire_date
FROM employees
ORDER BY hire_date ASC ;
DESC: 降序
SELECT last_name, job_id, department_id, hire_date
FROM employees
ORDER BY hire_date DESC ;
SELECT last_name, job_id, department_id, hire_date
FROM employees
ORDER BY hire_date ;
原文：http://www.cnblogs.com/adada/p/7241337.html