逻辑运算符
逻辑运算符用来判断表达式的真假。如果表达式是真，结果返回 1。如果表达式是假，结果返回 0。
1、与
mysql> select 2 and 0;
+---------+
| 2 and 0 |
+---------+
| 0 |
+---------+
mysql> select 2 and 1;
+---------+
| 2 and 1 |
+---------+
| 1 |
+---------+
2、或
mysql> select 2 or 0;
+--------+
| 2 or 0 |
+--------+
| 1 |
+--------+
mysql> select 2 or 1;
+--------+
| 2 or 1 |
+--------+
| 1 |
+--------+
mysql> select 0 or 0;
+--------+
| 0 or 0 |
+--------+
| 0 |
+--------+
mysql> select 1 || 0;
+--------+
| 1 || 0 |
+--------+
| 1 |
+--------+
3、非
mysql> select not 1;
+-------+
| not 1 |
+-------+
| 0 |
+-------+
mysql> select !0;
+----+
| !0 |
+----+
| 1 |
+----+
4、异或
mysql> select 1 xor 1;
+---------+
| 1 xor 1 |
+---------+
| 0 |
+---------+
mysql> select 0 xor 0;
+---------+
| 0 xor 0 |
+---------+
| 0 |
+---------+
mysql> select 1 xor 0;
+---------+
| 1 xor 0 |
+---------+
| 1 |
+---------+
mysql> select null or 1;
+-----------+
| null or 1 |
+-----------+
| 1 |
+-----------+
mysql> select 1 ^ 0;
+-------+
| 1 ^ 0 |
+-------+
| 1 |
+-------+
位运算符
位运算符是在二进制数上进行计算的运算符。位运算会先将操作数变成二进制数，进行位运算。然后再将计算结果从二进制数变回十进制数。
1、按位与
mysql> select 3&5;
+-----+
| 3&5 |
+-----+
| 1 |
+-----+
2、按位或
mysql> select 3|5;
+-----+
| 3|5 |
+-----+
| 7 |
+-----+
3、按位异或
mysql> select 3^5;
+-----+
| 3^5 |
+-----+
| 6 |
+-----+
4、按位取反
mysql> select ~18446744073709551612;
+-----------------------+
| ~18446744073709551612 |
+-----------------------+
| 3 |
+-----------------------+
5、按位右移
mysql> select 3>>1;
+------+
| 3>>1 |
+------+
| 1 |
+------+
6、按位左移
mysql> select 3<<1;
+------+
| 3<<1 |
+------+
| 6 |
+------+
运算符优先级
最低优先级为： :=。
最高优先级为： !、BINARY、 COLLATE。