运算符
算术运算符：
- 算术运算符有+, -, *, %(mod函数), /(div函数)。
比较运算符：
- 数字作为浮点数比较，字符串以不区分大小写的方式进行比较。
mysql> SELECT 10 BETWEEN 10 AND 20, 9 BETWEEN 10 AND 20;
+----------------------+---------------------+
| 10 BETWEEN 10 AND 20 | 9 BETWEEN 10 AND 20 |
+----------------------+---------------------+
| 1 | 0 |
+----------------------+---------------------+
- regexp则用正则表达式进行匹配，如：
mysql> SELECT 'abcdef' regexp 'ab', 'abcdefg' regexp 'k';
+----------------------+----------------------+
| 'abcdef' regexp 'ab' | 'abcdefg' regexp 'k' |
+----------------------+----------------------+
| 1 | 0 |
+----------------------+----------------------+逻辑运算符：
MySQL中包含的逻辑运算符：
分别对几种逻辑运算符进行描述：
mysql> SELECT NOT 0, NOT 1 , NOT NULL;
+-------+-------+----------+
| NOT 0 | NOT 1 | NOT NULL |
+-------+-------+----------+
| 1 | 0 | NULL |
+-------+-------+----------+ 
mysql> SELECT 1 AND 1, 0 AND 1, 3 AND 1, 1 AND NULL;
+---------+---------+---------+------------+
| 1 AND 1 | 0 AND 1 | 3 AND 1 | 1 AND NULL |
+---------+---------+---------+------------+
| 1 | 0 | 1 | NULL |
+---------+---------+---------+------------+
mysql> SELECT 1 OR 0, 0 OR 0, 1 OR NULL, 1 OR 1, NULL OR NULL;
+--------+--------+-----------+--------+--------------+
| 1 OR 0 | 0 OR 0 | 1 OR NULL | 1 OR 1 | NULL OR NULL |
+--------+--------+-----------+--------+--------------+
| 1 | 0 | 1 | 1 | NULL |
+--------+--------+-----------+--------+--------------+
mysql> SELECT 1 XOR 1, 0 XOR 0, 1 XOR 0, 0 XOR 1, NULL XOR 1;
+---------+---------+---------+---------+------------+
| 1 XOR 1 | 0 XOR 0 | 1 XOR 0 | 0 XOR 1 | NULL XOR 1 |
+---------+---------+---------+---------+------------+
| 0 | 0 | 1 | 1 | NULL |
+---------+---------+---------+---------+------------+位运算符：
MySQL5.0支持的位运算符：
分别介绍这几种位运算：
mysql> SELECT 2&3, 2&3&4;
+-----+-------+
| 2&3 | 2&3&4 |
+-----+-------+
| 2 | 0 |
+-----+-------+
mysql> SELECT 2|3, 2|3|4;
+-----+-------+
| 2|3 | 2|3|4 |
+-----+-------+
| 3 | 7 |
+-----+-------+
mysql> SELECT 2^3;
+-----+
| 2^3 |
+-----+
| 1 |
+-----+
mysql> SELECT ~1, ~18446744073709551614;
+----------------------+-----------------------+
| ~1 | ~18446744073709551614 |
+----------------------+-----------------------+
| 18446744073709551614 | 1 |
+----------------------+-----------------------+
mysql> SELECT 100>>3;
+--------+
| 100>>3 |
+--------+
| 12 |
+--------+
mysql> SELECT 100<<3;
+--------+
| 100<<3 |
+--------+
| 800 |
+--------+运算符的优先级：
具体的运算符的细节可参考官网：
http://dev.mysql.com/doc/refman/5.7/en/non-typed-operators.html
不吝指正。
