发布于 2015-07-25 11:52:56 | 197 次阅读 | 评论: 0 | 来源: 网络整理
位运算符位和执行位位操作。真值表 & 和 | 如下：
| p | q | p & q | p | q |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 |
| 1 | 1 | 1 | 1 |
| 1 | 0 | 0 | 1 |
假设，如果A=60和B=13;现在以二进制格式将如下：
A = 0011 1100
B = 0000 1101
-----------------
A&B = 0000 1100
A|B = 0011 1101
~A = 1100 0011
下表中列出的位运算符支持SQLite语言。假设变量A=60和变量B=13，则：
| 运算符 | 描述 | 实例 |
|---|---|---|
| & | Binary AND Operator copies a bit to the result if it exists in both operands. | (A & B) will give 12 which is 0000 1100 |
| | | Binary OR Operator copies a bit if it exists in either operand. | (A | B) will give 61 which is 0011 1101 |
| ~ | Binary Ones Complement Operator is unary and has the effect of 'flipping' bits. | (~A ) will give -61 which is 1100 0011 in 2's complement form due to a signed binary number. |
| << | Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. | A << 2 will give 240 which is 1111 0000 |
| >> | Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand. | A >> 2 will give 15 which is 0000 1111 |
下面是简单的例子显示使用SQLite的算术运算符：
sqlite> .mode line
sqlite> select 60 | 13;
60 | 13 = 61
sqlite> select 60 & 13;
60 & 13 = 12
sqlite> select 60 ^ 13;
10 * 20 = 200
sqlite> select (~60);
(~60) = -61
sqlite> select (60 << 2);
(60 << 2) = 240
sqlite> select (60 >> 2);
(60 >> 2) = 15