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邏輯運(yùn)算符
邏輯運(yùn)算符用來(lái)判斷表達(dá)式的真假。如果表達(dá)式是真,結(jié)果返回 1。如果表達(dá)式是假,結(jié)果返回 0。
運(yùn)算符號(hào) | 作用 |
---|---|
NOT 或 ! | 邏輯非 |
AND | 邏輯與 |
OR | 邏輯或 |
XOR | 邏輯異或 |
1、與
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、異或
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 |
+-------+
位運(yùn)算符
位運(yùn)算符是在二進(jìn)制數(shù)上進(jìn)行計(jì)算的運(yùn)算符。位運(yùn)算會(huì)先將操作數(shù)變成二進(jìn)制數(shù),進(jìn)行位運(yùn)算。然后再將計(jì)算結(jié)果從二進(jìn)制數(shù)變回十進(jìn)制數(shù)。
運(yùn)算符號(hào) | 作用 |
---|---|
& | 按位與 |
丨 | 按位或 |
^ | 按位異或 |
! | 取反 |
<< | 左移 |
>> | 右移 |
1、按位與
mysql> select 3&5;
+-----+
| 3&5 |
+-----+
| 1 |
+-----+
2、按位或
mysql> select 3|5;
+-----+
| 3|5 |
+-----+
| 7 |
+-----+
3、按位異或
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 |
+------+
運(yùn)算符優(yōu)先級(jí)
最低優(yōu)先級(jí)為: :=。
最高優(yōu)先級(jí)為: !、BINARY、 COLLATE。