13、mysql运算符

mysql主要有算数运算符、比较运算符、逻辑运算符、位运算符

1、算数运算符

+                 select 1+2;

-                  select 1-2;

*                  select 1* 2;

/ 或div         select 1/2;   or  select 1 div 2;

% 或 mod   select 1%2; or select 1 mod 2;

2、比较运算符

=               select 2=3;

<>  !=        select 2<>3;

>               select 2>3;

<               select 2<3;

<=             select 2<=3;

>=             select 2>=3

between   select 5 between 0 and 10;

not between select 5 not between 0 and 10;

in               select 5 in (1,2,3,4,5)

not in         select 5 not in (1,2,3,4,5)

<=>   严格比较两个null值是否相等，两个操作码均为null时，值为1，当一个操作码为null时，值为0 select 1<=>2 ;select null<=>null;

like   select '123456' like '12%';

is null    select null is null;  

 is not null  select 'a' is not null;

regexp   或rlike 正则式匹配   select 'beijing' regexp 'jing';

3、逻辑运算符

not ! and or xor

select 2 and 0;

select 2and 1;

select 2 or 0;

select 2 or 1;

select not 1;

select !0;

select 1 xor 1;

4、位运算符

& | ^ ! << >>

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 |
+------+

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运算符优先级

最低优先级为： :=。

最高优先级为： !、BINARY、 COLLATE。