mysql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 |
+-------+