【MySQL】 基本查询(上)

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本篇主题：【MySQL】 基本查询(上)
发布时间：2025.2.14
隶属专栏：MySQL

CRUD : Create(创建), Retrieve(读取)，Update(更新)，Delete（删除）

Create

基本知识

语法:

INSERT [INTO] table_name[(column [, column] ...)]VALUES (value_list) [, (value_list)] ...

案例:

mysql> create table students(-> id int unsigned primary key auto_increment,-> sn int not null unique key,-> name varchar(20) not null,-> qq varchar(32) unique key-> );
Query OK, 0 rows affected (0.02 sec)mysql> desc students;
+-------+------------------+------+-----+---------+----------------+
| Field | Type             | Null | Key | Default | Extra          |
+-------+------------------+------+-----+---------+----------------+
| id    | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| sn    | int(11)          | NO   | UNI | NULL    |                |
| name  | varchar(20)      | NO   |     | NULL    |                |
| qq    | varchar(32)      | YES  | UNI | NULL    |                |
+-------+------------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

直接插入

单行数据，指定列插入

into 可以省略，但是建议带上。

mysql> insert into students (sn, name, qq) values (123, '张飞', '4567890');
Query OK, 1 row affected (0.00 sec)mysql> select * from students;
+----+-----+--------+---------+
| id | sn  | name   | qq      |
+----+-----+--------+---------+
|  1 | 123 | 张飞   | 4567890 |
+----+-----+--------+---------+
1 row in set (0.00 sec)

单行数据，全列插入

into 可以省略，但是建议带上。

mysql> insert into students values (2, 124, '刘备', '4567891');
Query OK, 1 row affected (0.00 sec)mysql> select * from students;
+----+-----+--------+---------+
| id | sn  | name   | qq      |
+----+-----+--------+---------+
|  1 | 123 | 张飞   | 4567890 |
|  2 | 124 | 刘备   | 4567891 |
+----+-----+--------+---------+
2 rows in set (0.00 sec)

多行数据，指定列插入

每组数据之间用,(英文符号)隔开

mysql> insert into students (sn, name, qq) values (125, '关羽', '4562890'),(126, '诸葛亮', '423613719'),(127, '赵云', '3728140');
Query OK, 3 rows affected (0.01 sec)
Records: 3  Duplicates: 0  Warnings: 0mysql> select * from students;
+----+-----+-----------+-----------+
| id | sn  | name      | qq        |
+----+-----+-----------+-----------+
|  1 | 123 | 张飞      | 4567890   |
|  2 | 124 | 刘备      | 4567891   |
|  3 | 125 | 关羽      | 4562890   |
|  4 | 126 | 诸葛亮    | 423613719 |
|  5 | 127 | 赵云      | 3728140   |
+----+-----+-----------+-----------+
5 rows in set (0.00 sec)

多行数据，全列插入

每组数据之间用,(英文符号)隔开

mysql> insert into students values (10, 128, '曹操', '45637891'),(11, 129, '许攸','14723193'),(12, 130, '许褚','4723012');
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0mysql> select * from students;
+----+-----+-----------+-----------+
| id | sn  | name      | qq        |
+----+-----+-----------+-----------+
|  1 | 123 | 张飞      | 4567890   |
|  2 | 124 | 刘备      | 4567891   |
|  3 | 125 | 关羽      | 4562890   |
|  4 | 126 | 诸葛亮    | 423613719 |
|  5 | 127 | 赵云      | 3728140   |
| 10 | 128 | 曹操      | 45637891  |
| 11 | 129 | 许攸      | 14723193  |
| 12 | 130 | 许褚      | 4723012   |
+----+-----+-----------+-----------+
8 rows in set (0.00 sec)

插入替换

主键或者唯一键冲突

-- 主键冲突
mysql> insert into students values (12, 133, '荀彧', '45167891');
ERROR 1062 (23000): Duplicate entry '12' for key 'PRIMARY'-- 唯一键冲突
mysql> insert into students values (14, 132, '荀彧', '45167891');
ERROR 1062 (23000): Duplicate entry '132' for key 'sn'

插入时更新

语法：

INSERT ... ON DUPLICATE KEY UPDATE

案例：

mysql> insert into students values (11, 131, 'xuyou', '112121') on duplicate key update sn=131, name='xuyou', qq='112121';
Query OK, 2 rows affected (0.00 sec)mysql> insert into students values (13, 132, '貂蝉', '1121211') on duplicate key update sn=132, name='貂蝉', qq='1121211';
Query OK, 1 row affected (0.01 sec)mysql> insert into students values (13, 132, '貂蝉', '1121211') on duplicate key update sn=132, name='貂蝉', qq='1121211';
Query OK, 0 rows affected (0.00 sec)mysql> select * from students;
+----+-----+-----------+-----------+
| id | sn  | name      | qq        |
+----+-----+-----------+-----------+
|  1 | 123 | 张飞      | 4567890   |
|  2 | 124 | 刘备      | 4567891   |
|  3 | 125 | 关羽      | 4562890   |
|  4 | 126 | 诸葛亮    | 423613719 |
|  5 | 127 | 赵云      | 3728140   |
| 10 | 128 | 曹操      | 45637891  |
| 11 | 131 | xuyou     | 112121    |
| 12 | 130 | 许褚      | 4723012   |
| 13 | 132 | 貂蝉      | 1121211   |
+----+-----+-----------+-----------+
9 rows in set (0.00 sec)

受影响的行数不同，表示插入的情况也不同。

• 0 row affected: 表中有冲突数据，但冲突数据的值和 update 的值相等
• 1 row affected: 表中没有冲突数据，数据被插入
• 2 row affected: 表中有冲突数据，并且数据已经被更新

通过 MySQL 函数获取受到影响的数据行数

mysql> select row_count();
+-------------+
| row_count() |
+-------------+
|           0 |
+-------------+
1 row in set (0.00 sec)

插入时替换

• 主键 或者 唯一键 没有冲突，则直接插入
• 主键 或者 唯一键 如果冲突，则删除后再插入

mysql> replace into students (sn, name, qq) values (133, '许攸', '12345612');
Query OK, 1 row affected (0.01 sec)mysql> replace into students (sn, name, qq) values (133, '许攸1', '12345612');
Query OK, 2 rows affected (0.02 sec)mysql> replace into students (sn, name, qq) values (132, '许攸1', '12345612');
Query OK, 3 rows affected (0.01 sec)mysql> select * from students;
+----+-----+-----------+-----------+
| id | sn  | name      | qq        |
+----+-----+-----------+-----------+
|  1 | 123 | 张飞      | 4567890   |
|  2 | 124 | 刘备      | 4567891   |
|  3 | 125 | 关羽      | 4562890   |
|  4 | 126 | 诸葛亮    | 423613719 |
|  5 | 127 | 赵云      | 3728140   |
| 10 | 128 | 曹操      | 45637891  |
| 11 | 131 | xuyou     | 112121    |
| 12 | 130 | 许褚      | 4723012   |
| 16 | 132 | 许攸1     | 12345612  |
+----+-----+-----------+-----------+
9 rows in set (0.00 sec)

受影响的行数不同，表示插入的情况也不同。

• 1 row affected: 表中没有冲突数据，数据被插入
• 2 row affected: 表中有一行冲突数据，删除后重新插入
• n row affected: 表中有 n-1 行冲突数据，删除后重新插入

Retrieve

基本知识

语法：

SELECT[DISTINCT] {* | {column [, column] ...}[FROM table_name][WHERE ...][ORDER BY column [ASC | DESC], ...]LIMIT ...

案例：

-- 创建表结构
mysql> CREATE TABLE exam_result (-> id INT UNSIGNED PRIMARY KEY AUTO_INCREMENT,-> name VARCHAR(20) NOT NULL COMMENT '同学姓名',-> chinese float DEFAULT 0.0 COMMENT '语文成绩',-> math float DEFAULT 0.0 COMMENT '数学成绩',-> english float DEFAULT 0.0 COMMENT '英语成绩'-> );
Query OK, 0 rows affected (0.01 sec)mysql> desc exam_result;
+---------+------------------+------+-----+---------+----------------+
| Field   | Type             | Null | Key | Default | Extra          |
+---------+------------------+------+-----+---------+----------------+
| id      | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| name    | varchar(20)      | NO   |     | NULL    |                |
| chinese | float            | YES  |     | 0       |                |
| math    | float            | YES  |     | 0       |                |
| english | float            | YES  |     | 0       |                |
+---------+------------------+------+-----+---------+----------------+
5 rows in set (0.00 sec)-- 插入测试数据
mysql> INSERT INTO exam_result (name, chinese, math, english) VALUES-> ('唐三藏', 67, 98, 56),-> ('孙悟空', 87, 78, 77),-> ('猪悟能', 88, 98, 90),-> ('曹孟德', 82, 84, 67),-> ('刘玄德', 55, 85, 45),-> ('孙权', 70, 73, 78),-> ('宋公明', 75, 65, 30);
Query OK, 7 rows affected (0.00 sec)
Records: 7  Duplicates: 0  Warnings: 0

select 列

全列查询

通常情况下不建议使用 * 进行全列查询

1. 查询的列越多，意味着需要传输的数据量越大；
2. 可能会影响到索引的使用。（索引待后面文章讲解）

mysql> select * from exam_result;
+----+-----------+---------+------+---------+
| id | name      | chinese | math | english |
+----+-----------+---------+------+---------+
|  1 | 唐三藏    |      67 |   98 |      56 |
|  2 | 孙悟空    |      87 |   78 |      77 |
|  3 | 猪悟能    |      88 |   98 |      90 |
|  4 | 曹孟德    |      82 |   84 |      67 |
|  5 | 刘玄德    |      55 |   85 |      45 |
|  6 | 孙权      |      70 |   73 |      78 |
|  7 | 宋公明    |      75 |   65 |      30 |
+----+-----------+---------+------+---------+
7 rows in set (0.00 sec)

指定列进行查询

指定列的顺序不需要按定义表的顺序来

mysql> select id, math, name from exam_result;
+----+------+-----------+
| id | math | name      |
+----+------+-----------+
|  1 |   98 | 唐三藏    |
|  2 |   78 | 孙悟空    |
|  3 |   98 | 猪悟能    |
|  4 |   84 | 曹孟德    |
|  5 |   85 | 刘玄德    |
|  6 |   73 | 孙权      |
|  7 |   65 | 宋公明    |
+----+------+-----------+
7 rows in set (0.00 sec)

查询字段为表达式

1. 表达式不包含字段

mysql> select id, name, 10 from exam_result;
+----+-----------+----+
| id | name      | 10 |
+----+-----------+----+
|  1 | 唐三藏    | 10 |
|  2 | 孙悟空    | 10 |
|  3 | 猪悟能    | 10 |
|  4 | 曹孟德    | 10 |
|  5 | 刘玄德    | 10 |
|  6 | 孙权      | 10 |
|  7 | 宋公明    | 10 |
+----+-----------+----+
7 rows in set (0.00 sec)

2. 表达式包含一个字段

mysql> select id, name, 10+math from exam_result;
+----+-----------+---------+
| id | name      | 10+math |
+----+-----------+---------+
|  1 | 唐三藏    |     108 |
|  2 | 孙悟空    |      88 |
|  3 | 猪悟能    |     108 |
|  4 | 曹孟德    |      94 |
|  5 | 刘玄德    |      95 |
|  6 | 孙权      |      83 |
|  7 | 宋公明    |      75 |
+----+-----------+---------+
7 rows in set (0.03 sec)

3. 表达式包含多个字段

mysql> select id, name, chinese+math+english from exam_result;
+----+-----------+----------------------+
| id | name      | chinese+math+english |
+----+-----------+----------------------+
|  1 | 唐三藏    |                  221 |
|  2 | 孙悟空    |                  242 |
|  3 | 猪悟能    |                  276 |
|  4 | 曹孟德    |                  233 |
|  5 | 刘玄德    |                  185 |
|  6 | 孙权      |                  221 |
|  7 | 宋公明    |                  170 |
+----+-----------+----------------------+
7 rows in set (0.00 sec)

为查询结果指定别名

语法：

SELECT column [AS] alias_name [...] FROM table_name;

as可以省略

案例：

mysql> select id, name, chinese+math+english as total from exam_result;
+----+-----------+-------+
| id | name      | total |
+----+-----------+-------+
|  1 | 唐三藏    |   221 |
|  2 | 孙悟空    |   242 |
|  3 | 猪悟能    |   276 |
|  4 | 曹孟德    |   233 |
|  5 | 刘玄德    |   185 |
|  6 | 孙权      |   221 |
|  7 | 宋公明    |   170 |
+----+-----------+-------+
7 rows in set (0.00 sec)

结果去重

去重前

mysql> select math from exam_result;
+------+
| math |
+------+
|   98 |
|   78 |
|   98 |
|   84 |
|   85 |
|   73 |
|   65 |
+------+
7 rows in set (0.00 sec)

去重后

mysql> select distinct math from exam_result;
+------+
| math |
+------+
|   98 |
|   78 |
|   84 |
|   85 |
|   73 |
|   65 |
+------+
6 rows in set (0.00 sec)

where条件

比较运算符

运算符	说明
> , >=, <, <=	大于，大于等于，小于，小于等于
=	等于，NULL 不安全，例如 NULL = NULL 的结果是 NULL
<=>	等于，NULL 安全，例如 NULL <=> NULL 的结果是 TRUE(1)
!=, <>	不等于
BETWEEN a0 AND a1	范围匹配，[a0, a1]，如果 a0 <= value <= a1，返回 TRUE(1)
IN (option, …)	如果是 option 中的任意一个，返回 TRUE(1)
IS NULL	是 NULL
IS NOT NULL	不是 NULL
LIKE	模糊匹配。% 表示任意多个（包括 0 个）任意字符；_ 表示任意一个字符

逻辑运算符

运算符	说明
AND	多个条件必须都为 TRUE(1)，结果才是 TRUE(1)
OR	任意一个条件为 TRUE(1), 结果为 TRUE(1)
NOT	条件为 TRUE(1)，结过为 FALSE(0)

案例

1. 英语不及格的同学及英语成绩(<60)

mysql> select name, english from exam_result where english<60;
+-----------+---------+
| name      | english |
+-----------+---------+
| 唐三藏    |      56 |
| 刘玄德    |      45 |
| 宋公明    |      30 |
+-----------+---------+
3 rows in set (0.00 sec)

2. 语文成绩在 [80, 90] 分的同学及语文成绩

使用 AND 进行条件连接

mysql> select name, chinese from exam_result where chinese>=80 and chinese<=90;
+-----------+---------+
| name      | chinese |
+-----------+---------+
| 孙悟空    |      87 |
| 猪悟能    |      88 |
| 曹孟德    |      82 |
+-----------+---------+
3 rows in set (0.00 sec)

使用 BETWEEN ... AND ... 条件

mysql> select name, chinese from exam_result where chinese between 80 and 90;
+-----------+---------+
| name      | chinese |
+-----------+---------+
| 孙悟空    |      87 |
| 猪悟能    |      88 |
| 曹孟德    |      82 |
+-----------+---------+
3 rows in set (0.00 sec)

3. 数学成绩是 58 或者 59 或者 98 或者 99 分的同学及数学成绩的同学及数学成绩

使用 OR 进行条件连接

mysql> select name, math from exam_result where math=58 or math=59 or math=98 or math=99;
+-----------+------+
| name      | math |
+-----------+------+
| 唐三藏    |   98 |
| 猪悟能    |   98 |
+-----------+------+
2 rows in set (0.01 sec)

使用 IN 条件

mysql> select name, math from exam_result where math in (58, 59, 98, 99);
+-----------+------+
| name      | math |
+-----------+------+
| 唐三藏    |   98 |
| 猪悟能    |   98 |
+-----------+------+
2 rows in set (0.01 sec)

4. 姓孙的同学 及 孙某同学

% 匹配任意多个（包括 0 个）任意字符

mysql> select name from exam_result where name like '孙%';
+-----------+
| name      |
+-----------+
| 孙悟空    |
| 孙权      |
+-----------+
2 rows in set (0.00 sec)

_ 匹配严格的一个任意字符

mysql> select name from exam_result where name like '孙_';
+--------+
| name   |
+--------+
| 孙权   |
+--------+
1 row in set (0.00 sec)

5. 语文成绩好于英语成绩的同学

WHERE 条件中比较运算符两侧都是字段

mysql> select name, chinese, english from exam_result where chinese > english;
+-----------+---------+---------+
| name      | chinese | english |
+-----------+---------+---------+
| 唐三藏    |      67 |      56 |
| 孙悟空    |      87 |      77 |
| 曹孟德    |      82 |      67 |
| 刘玄德    |      55 |      45 |
| 宋公明    |      75 |      30 |
+-----------+---------+---------+
5 rows in set (0.00 sec)

6. 总分在 200 分以下的同学

WHERE 条件中使用表达式
别名不能用在 WHERE 条件中

mysql> select name, chinese+math+english as 总分 from exam_result where chinese+math+english<200;
+-----------+--------+
| name      | 总分   |
+-----------+--------+
| 刘玄德    |    185 |
| 宋公明    |    170 |
+-----------+--------+
2 rows in set (0.00 sec)

7. 语文成绩 > 80 并且不姓孙的同学

AND 与 NOT 的使用

mysql> select name, chinese from exam_result where chinese>80 and name not like '孙%';
+-----------+---------+
| name      | chinese |
+-----------+---------+
| 猪悟能    |      88 |
| 曹孟德    |      82 |
+-----------+---------+
2 rows in set (0.00 sec)

8. 孙某同学，否则要求总成绩 > 200 并且 语文成绩 < 数学成绩 并且 英语成绩 > 80

综合查询

mysql> select name, chinese, math, english, chinese+math+english as 总分 ->from exam_result ->where name like '孙_' or (chinese+math+english>200 and chinese<math and english>80);
+-----------+---------+------+---------+--------+
| name      | chinese | math | english | 总分   |
+-----------+---------+------+---------+--------+
| 猪悟能    |      88 |   98 |      90 |    276 |
| 孙权      |      70 |   73 |      78 |    221 |
+-----------+---------+------+---------+--------+
2 rows in set (0.00 sec)

9. NULL 的查询

mysql> create table test(-> id int, -> name varchar(20)-> );
Query OK, 0 rows affected (0.01 sec)mysql> insert into test values (1,'张三');
Query OK, 1 row affected (0.00 sec)mysql> insert into test values (null,'张三');
Query OK, 1 row affected (0.00 sec)mysql> insert into test values (1,null);
Query OK, 1 row affected (0.00 sec)mysql> insert into test values (null,null);
Query OK, 1 row affected (0.00 sec)mysql> insert into test values (1,'');
Query OK, 1 row affected (0.00 sec)mysql> select * from test;
+------+--------+
| id   | name   |
+------+--------+
|    1 | 张三   |
| NULL | 张三   |
|    1 | NULL   |
| NULL | NULL   |
|    1 |        |
+------+--------+
5 rows in set (0.00 sec)mysql> select * from test where name is null;
+------+------+
| id   | name |
+------+------+
|    1 | NULL |
| NULL | NULL |
+------+------+
2 rows in set (0.00 sec)mysql> select * from test where name is  not null;
+------+--------+
| id   | name   |
+------+--------+
|    1 | 张三   |
| NULL | 张三   |
|    1 |        |
+------+--------+
3 rows in set (0.00 sec)

NULL 和 NULL的比较，= 和<=>的区别

SELECT NULL = NULL, NULL = 1, NULL = 0;
+-------------+----------+----------+
| NULL = NULL | NULL = 1 | NULL = 0 |
+-------------+----------+----------+
|        NULL |     NULL |     NULL |
+-------------+----------+----------+
1 row in set (0.00 sec)SELECT NULL <=> NULL, NULL <=> 1, NULL <=> 0;
+---------------+------------+------------+
| NULL <=> NULL | NULL <=> 1 | NULL <=> 0 |
+---------------+------------+------------+
|             1 |          0 |          0 |
+---------------+------------+------------+
1 row in set (0.00 sec)

结果排序

语法：

SELECT ... FROM table_name [WHERE ...]
ORDER BY column [ASC|DESC], [...];

• ASC 为升序（从小到大）
• DESC 为降序（从大到小）
• 默认为 ASC
• 没有 ORDER BY 子句的查询，返回的顺序是未定义的，永远不要依赖这个顺序

案例：

1. 同学及数学成绩，按数学成绩升序显示

mysql> select name, math from exam_result order by math asc;
+-----------+------+
| name      | math |
+-----------+------+
| 宋公明    |   65 |
| 孙权      |   73 |
| 孙悟空    |   78 |
| 曹孟德    |   84 |
| 刘玄德    |   85 |
| 唐三藏    |   98 |
| 猪悟能    |   98 |
+-----------+------+
7 rows in set (0.02 sec)

2. id及姓名，按姓名排序显示

NULL 视为比任何值都小，升序出现在最上面

mysql> select id,name from test order by name asc;
+------+--------+
| id   | name   |
+------+--------+
|    1 | NULL   |
| NULL | NULL   |
|    1 |        |
|    1 | 张三   |
| NULL | 张三   |
+------+--------+
5 rows in set (0.00 sec)

NULL 视为比任何值都小，降序出现在最下面

mysql> select id,name from test order by name desc;
+------+--------+
| id   | name   |
+------+--------+
|    1 | 张三   |
| NULL | 张三   |
|    1 |        |
|    1 | NULL   |
| NULL | NULL   |
+------+--------+
5 rows in set (0.00 sec)

3. 查询同学各门成绩，依次按 数学降序，英语升序，语文升序的方式显示

多字段排序，排序优先级随书写顺序

mysql> select name, math, english, chinese from exam_result order by math desc, english asc, chinese asc;
+-----------+------+---------+---------+
| name      | math | english | chinese |
+-----------+------+---------+---------+
| 唐三藏    |   98 |      56 |      67 |
| 猪悟能    |   98 |      90 |      88 |
| 刘玄德    |   85 |      45 |      55 |
| 曹孟德    |   84 |      67 |      82 |
| 孙悟空    |   78 |      77 |      87 |
| 孙权      |   73 |      78 |      70 |
| 宋公明    |   65 |      30 |      75 |
+-----------+------+---------+---------+
7 rows in set (0.00 sec)

4. 查询同学及总分，由高到低

ORDER BY 中可以使用表达式

mysql> select name, chinese+english+math from exam_result order by chinese+english+math desc;
+-----------+----------------------+
| name      | chinese+english+math |
+-----------+----------------------+
| 猪悟能    |                  276 |
| 孙悟空    |                  242 |
| 曹孟德    |                  233 |
| 唐三藏    |                  221 |
| 孙权      |                  221 |
| 刘玄德    |                  185 |
| 宋公明    |                  170 |
+-----------+----------------------+
7 rows in set (0.00 sec)

ORDER BY 子句中可以使用列别名

mysql> select name, chinese+english+math as total from exam_result order by total desc;
+-----------+-------+
| name      | total |
+-----------+-------+
| 猪悟能    |   276 |
| 孙悟空    |   242 |
| 曹孟德    |   233 |
| 唐三藏    |   221 |
| 孙权      |   221 |
| 刘玄德    |   185 |
| 宋公明    |   170 |
+-----------+-------+
7 rows in set (0.00 sec)

5. 查询姓孙的同学或者姓曹的同学数学成绩，结果按数学成绩由高到低显示

结合WHERE 子句 和 ORDER BY 子句

mysql> select name, math from exam_result-> where name like '孙%' or name like '曹%'-> order by math desc;
+-----------+------+
| name      | math |
+-----------+------+
| 曹孟德    |   84 |
| 孙悟空    |   78 |
| 孙权      |   73 |
+-----------+------+
3 rows in set (0.00 sec)

筛选分页结果

语法

起始下标为 0

1. 从 s 开始，筛选 n 条结果

SELECT ... FROM table_name [WHERE ...] [ORDER BY ...] LIMIT s, n

2. 从 0 开始，筛选 n 条结果

SELECT ... FROM table_name [WHERE ...] [ORDER BY ...] LIMIT n;
;

3. 从 s 开始，筛选 n 条结果，比第二种用法更明确，建议使用

SELECT ... FROM table_name [WHERE ...] [ORDER BY ...] LIMIT n OFFSET s;

只有数据准备好了，你才要显示，limit的本质功能是显示.

案例

建议：对未知表进行查询时，最好加一条 LIMIT 1，避免因为表中数据过大，查询全表数据导致数据库卡死按 id 进行分页，每页 3 条记录，分别显示1、2、3页

第一页

ysql> select id, name, chinese, math, english from exam_result order by id limit 3 offset 0;
+----+-----------+---------+------+---------+
| id | name      | chinese | math | english |
+----+-----------+---------+------+---------+
|  1 | 唐三藏    |      67 |   98 |      56 |
|  2 | 孙悟空    |      87 |   78 |      77 |
|  3 | 猪悟能    |      88 |   98 |      90 |
+----+-----------+---------+------+---------+
3 rows in set (0.00 sec)

第二页

mysql> select id, name, chinese, math, english from exam_result order by id limit 3 offset 3;
+----+-----------+---------+------+---------+
| id | name      | chinese | math | english |
+----+-----------+---------+------+---------+
|  4 | 曹孟德    |      82 |   84 |      67 |
|  5 | 刘玄德    |      55 |   85 |      45 |
|  6 | 孙权      |      70 |   73 |      78 |
+----+-----------+---------+------+---------+
3 rows in set (0.00 sec)

第三页，如果结果不足 3 个，不会有影响

mysql> select id, name, chinese, math, english from exam_result order by id limit 3 offset 6;
+----+-----------+---------+------+---------+
| id | name      | chinese | math | english |
+----+-----------+---------+------+---------+
|  7 | 宋公明    |      75 |   65 |      30 |
+----+-----------+---------+------+---------+
1 row in set (0.00 sec)

⚠️ 写在最后：以上内容是我在学习以后得一些总结和概括，如有错误或者需要补充的地方欢迎各位大佬评论或者私信我交流！！！