mysql运算符大全、优先级及实例讲解

一、算术运算符

1、加 

<code class="sql">mysql> select 1+2;
+-----+
| 1+2 |
+-----+
|   3 |
+-----+</code>

2、减

<code class="sql">mysql> select 1-2;
+-----+
| 1-2 |
+-----+
|  -1 |
+-----+</code>

3、乘

<code class="sql">mysql> select 2*3;
+-----+
| 2*3 |
+-----+
|   6 |
+-----+</code>

4、除

<code class="sql">mysql> select 2/3;
+--------+
| 2/3    |
+--------+
| 0.6667 |
+--------+</code>

5、商

<code class="sql">mysql> select 10 DIV 4;
+----------+
| 10 DIV 4 |
+----------+
|        2 |
+----------+</code>

6、取余

<code class="sql">mysql> select 10 MOD 4;
+----------+
| 10 MOD 4 |
+----------+
|        2 |
+----------+</code>

 

二、比较运算符

1、等于

<code class="sql">mysql> select 2=3;
+-----+
| 2=3 |
+-----+
|   0 |
+-----+


mysql> select NULL = NULL;
+-------------+
| NULL = NULL |
+-------------+
|        NULL |
+-------------+</code>

2、不等于

<code class="sql">mysql> select 23;
+------+
| 23 |
+------+
|    1 |
+------+</code>

3、安全等于

与“=”的区别在于当两个操作码均为NULL时，其所得值为1而不为NULL，而当一个操作码为NULL时，其所得值为0而不为NULL。

<code class="sql">mysql> select 23;
+-------+
| 23 |
+-------+
|     0 |
+-------+


mysql> select null=null;
+-----------+
| null=null |
+-----------+
|      NULL |
+-----------+

        
mysql> select nullnull;
+-------------+
| nullnull |
+-------------+
|           1 |
+-------------+</code>

4、小于

<code class="sql">mysql> select 2</code>

5、小于等于

<code class="sql">mysql> select 2</code>

6、大于

<code class="sql">mysql> select 2>3;
+-----+
| 2>3 |
+-----+
|   0 |
+-----+</code>

7、大于等于

<code class="sql">mysql> select 2>=3;
+------+
| 2>=3 |
+------+
|    0 |
+------+</code>

8、BETWEEN

<code class="sql">mysql> select 5 between 1 and 10;
+--------------------+
| 5 between 1 and 10 |
+--------------------+
|                  1 |
+--------------------+</code>

9、IN

<code class="sql">mysql> select 5 in (1,2,3,4,5);
+------------------+
| 5 in (1,2,3,4,5) |
+------------------+
|                1 |
+------------------+</code>

10、NOT IN

<code class="sql">mysql> select 5 not in (1,2,3,4,5);
+----------------------+
| 5 not in (1,2,3,4,5) |
+----------------------+
|                    0 |
+----------------------+</code>

11、IS NULL

<code class="sql">mysql> select null is NULL;
+--------------+
| null is NULL |
+--------------+
|            1 |
+--------------+

mysql> select 'a' is NULL;
+-------------+
| 'a' is NULL |
+-------------+
|           0 |
+-------------+</code>

12、IS NOT NULL

<code class="sql">mysql> select null IS NOT NULL;
+------------------+
| null IS NOT NULL |
+------------------+
|                0 |
+------------------+

        
mysql> select 'a' IS NOT NULL;
+-----------------+
| 'a' IS NOT NULL |
+-----------------+
|               1 |
+-----------------+</code>

13、LIKE

<code class="sql">mysql> select '12345' like '12%';
+--------------------+
| '12345' like '12%' |
+--------------------+
|                  1 |
+--------------------+

mysql> select '12345' like '12_';
+--------------------+
| '12345' like '12_' |
+--------------------+
|                  0 |
+--------------------+</code>

14、REGEXP

<code class="sql">mysql> select 'beijing' REGEXP 'jing';
+-------------------------+
| 'beijing' REGEXP 'jing' |
+-------------------------+
|                       1 |
+-------------------------+

mysql> select 'beijing' REGEXP 'xi';
+-----------------------+
| 'beijing' REGEXP 'xi' |
+-----------------------+
|                     0 |
+-----------------------+</code>

 

三、逻辑运算符

1、与

<code class="sql">mysql> select 2 and 0;
+---------+
| 2 and 0 |
+---------+
|       0 |
+---------+

        
mysql> select 2 and 1;   
+---------+     
| 2 and 1 |      
+---------+      
|       1 |      
+---------+</code>

2、或

<code class="sql">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 |
+--------+</code>

3、非

<code class="sql">mysql> select not 1;
+-------+
| not 1 |
+-------+
|     0 |
+-------+

mysql> select !0;
+----+
| !0 |
+----+
|  1 |
+----+</code>

4、异或

<code class="sql">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 |
+-------+</code>

 

四、位运算符

1、按位与

<code class="sql">mysql> select 3&5;
+-----+
| 3&5 |
+-----+
|   1 |
+-----+</code>

2、按位或

<code class="sql">mysql> select 3|5;
+-----+
| 3|5 |
+-----+
|   7 |
+-----+</code>

3、按位异或

<code class="sql">mysql> select 3^5;
+-----+
| 3^5 |
+-----+
|   6 |
+-----+</code>

4、按位取反

<code class="sql">mysql> select ~18446744073709551612;
+-----------------------+
| ~18446744073709551612 |
+-----------------------+
|                     3 |
+-----------------------+</code>

5、按位右移  

<code class="sql">mysql> select 3>>1;
+------+
| 3>>1 |
+------+
|    1 |
+------+</code>

6、按位左移

<code class="sql">mysql> select 3</code>

 

五、运算符优先级顺序

最高优先级 :=

1 ||, OR, XOR

2 &&, AND

3 BETWEEN, CASE, WHEN, THEN, ELSE

4 =, , >=, >, , !=, IS, LIKE, REGEXP, IN

5 |

6 &

7 >

8 -, +

9 *, /, DIV, %, MOD

10 ^

11 - (unary minus), ~ (unary bit inversion)

12 !, NOT

最低优先级 BINARY, COLLATE