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【MySQL】查询语法简介

jingxiao

jingxiao

2019-07-01

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本篇文章主要简介下MySQL中where,group by ,order by ,limit,join,union ,union all,子表等查询语法。

测试数据准备
create table emp (
    empno numeric(4) not null,
    ename varchar(10),
    job varchar(9),
    mgr numeric(4),
    hiredate datetime,
    sal numeric(7, 2),
    comm numeric(7, 2),
    deptno numeric(2)
);

create table dept (
    deptno numeric(2),
    dname varchar(14),
    loc varchar(13)
);

create table salgrade (
    grade numeric,
    losal numeric,
    hisal numeric
);

insert into dept values (10, 'ACCOUNTING', 'NEW YORK');
insert into dept values (20, 'RESEARCH', 'DALLAS');
insert into dept values (30, 'SALES', 'CHICAGO');
insert into dept values (40, 'OPERATIONS', 'BOSTON');

insert into salgrade values (1, 700, 1200);
insert into salgrade values (2, 1201, 1400);
insert into salgrade values (3, 1401, 2000);
insert into salgrade values (4, 2001, 3000);
insert into salgrade values (5, 3001, 9999);

insert into emp values (7369, 'SMITH', 'CLERK', 7902, '1980-12-17', 800, null, 20);
insert into emp values (7499, 'ALLEN', 'SALESMAN', 7698, '1981-02-20', 1600, 300, 30);
insert into emp values (7521, 'WARD', 'SALESMAN', 7698, '1981-02-22', 1250, 500, 30);
insert into emp values (7566, 'JONES', 'MANAGER', 7839, '1981-04-02', 2975, null, 20);
insert into emp values (7654, 'MARTIN', 'SALESMAN', 7698, '1981-09-28', 1250, 1400, 30);
insert into emp values (7698, 'BLAKE', 'MANAGER', 7839, '1981-05-01', 2850, null, 30);
insert into emp values (7782, 'CLARK', 'MANAGER', 7839, '1981-06-09', 2450, null, 10);
insert into emp values (7788, 'SCOTT', 'ANALYST', 7566, '1982-12-09', 3000, null, 20);
insert into emp values (7839, 'KING', 'PRESIDENT', null, '1981-11-17', 5000, null, 10);
insert into emp values (7844, 'TURNER', 'SALESMAN', 7698, '1981-09-08', 1500, 0, 30);
insert into emp values (7876, 'ADAMS', 'CLERK', 7788, '1983-01-12', 1100, null, 20);
insert into emp values (7900, 'JAMES', 'CLERK', 7698, '1981-12-03', 950, null, 30);
insert into emp values (7902, 'FORD', 'ANALYST', 7566, '1981-12-03', 3000, null, 20);
insert into emp values (7934, 'MILLER', 'CLERK', 7782, '1982-01-23', 1300, null, 10);
1.模糊查询
mysql> select * from emp where ename like '%S%'; 
+-------+-------+---------+------+---------------------+---------+------+--------+
| empno | ename | job     | mgr  | hiredate            | sal     | comm | deptno |
+-------+-------+---------+------+---------------------+---------+------+--------+
|  7369 | SMITH | CLERK   | 7902 | 1980-12-17 00:00:00 |  800.00 | NULL |     20 |
|  7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL |     20 |
|  7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL |     20 |
|  7876 | ADAMS | CLERK   | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL |     20 |
|  7900 | JAMES | CLERK   | 7698 | 1981-12-03 00:00:00 |  950.00 | NULL |     30 |
+-------+-------+---------+------+---------------------+---------+------+--------+
5 rows in set (0.00 sec)

mysql> select * from emp where ename like 'S%'; 
+-------+-------+---------+------+---------------------+---------+------+--------+
| empno | ename | job     | mgr  | hiredate            | sal     | comm | deptno |
+-------+-------+---------+------+---------------------+---------+------+--------+
|  7369 | SMITH | CLERK   | 7902 | 1980-12-17 00:00:00 |  800.00 | NULL |     20 |
|  7788 | SCOTT | ANALYST | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL |     20 |
+-------+-------+---------+------+---------------------+---------+------+--------+
2 rows in set (0.01 sec)

mysql> select * from emp where ename like '%S';
+-------+-------+---------+------+---------------------+---------+------+--------+
| empno | ename | job     | mgr  | hiredate            | sal     | comm | deptno |
+-------+-------+---------+------+---------------------+---------+------+--------+
|  7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL |     20 |
|  7876 | ADAMS | CLERK   | 7788 | 1983-01-12 00:00:00 | 1100.00 | NULL |     20 |
|  7900 | JAMES | CLERK   | 7698 | 1981-12-03 00:00:00 |  950.00 | NULL |     30 |
+-------+-------+---------+------+---------------------+---------+------+--------+
3 rows in set (0.00 sec)

mysql> select * from emp where ename like '_O%';
+-------+-------+---------+------+---------------------+---------+------+--------+
| empno | ename | job     | mgr  | hiredate            | sal     | comm | deptno |
+-------+-------+---------+------+---------------------+---------+------+--------+
|  7566 | JONES | MANAGER | 7839 | 1981-04-02 00:00:00 | 2975.00 | NULL |     20 |
|  7902 | FORD  | ANALYST | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL |     20 |
+-------+-------+---------+------+---------------------+---------+------+--------+
2 rows in set (0.00 sec)
总结：
%表示任意0个或多个字符，可匹配任意类型和长度的字符；
_表示任意单个字符，匹配单个任意字符。
2.排序
mysql> select * from emp order by  sal;
+-------+--------+-----------+------+---------------------+---------+---------+--------+
| empno | ename  | job       | mgr  | hiredate            | sal     | comm    | deptno |
+-------+--------+-----------+------+---------------------+---------+---------+--------+
|  7369 | SMITH  | CLERK     | 7902 | 1980-12-17 00:00:00 |  800.00 |    NULL |     20 |
|  7900 | JAMES  | CLERK     | 7698 | 1981-12-03 00:00:00 |  950.00 |    NULL |     30 |
|  7876 | ADAMS  | CLERK     | 7788 | 1983-01-12 00:00:00 | 1100.00 |    NULL |     20 |
|  7521 | WARD   | SALESMAN  | 7698 | 1981-02-22 00:00:00 | 1250.00 |  500.00 |     30 |
|  7654 | MARTIN | SALESMAN  | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 |     30 |
|  7934 | MILLER | CLERK     | 7782 | 1982-01-23 00:00:00 | 1300.00 |    NULL |     10 |
|  7844 | TURNER | SALESMAN  | 7698 | 1981-09-08 00:00:00 | 1500.00 |    0.00 |     30 |
|  7499 | ALLEN  | SALESMAN  | 7698 | 1981-02-20 00:00:00 | 1600.00 |  300.00 |     30 |
|  7782 | CLARK  | MANAGER   | 7839 | 1981-06-09 00:00:00 | 2450.00 |    NULL |     10 |
|  7698 | BLAKE  | MANAGER   | 7839 | 1981-05-01 00:00:00 | 2850.00 |    NULL |     30 |
|  7566 | JONES  | MANAGER   | 7839 | 1981-04-02 00:00:00 | 2975.00 |    NULL |     20 |
|  7788 | SCOTT  | ANALYST   | 7566 | 1982-12-09 00:00:00 | 3000.00 |    NULL |     20 |
|  7902 | FORD   | ANALYST   | 7566 | 1981-12-03 00:00:00 | 3000.00 |    NULL |     20 |
|  7839 | KING   | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 |    NULL |     10 |
+-------+--------+-----------+------+---------------------+---------+---------+--------+
14 rows in set (0.00 sec)

mysql> select * from emp order by  sal asc;
+-------+--------+-----------+------+---------------------+---------+---------+--------+
| empno | ename  | job       | mgr  | hiredate            | sal     | comm    | deptno |
+-------+--------+-----------+------+---------------------+---------+---------+--------+
|  7369 | SMITH  | CLERK     | 7902 | 1980-12-17 00:00:00 |  800.00 |    NULL |     20 |
|  7900 | JAMES  | CLERK     | 7698 | 1981-12-03 00:00:00 |  950.00 |    NULL |     30 |
|  7876 | ADAMS  | CLERK     | 7788 | 1983-01-12 00:00:00 | 1100.00 |    NULL |     20 |
|  7521 | WARD   | SALESMAN  | 7698 | 1981-02-22 00:00:00 | 1250.00 |  500.00 |     30 |
|  7654 | MARTIN | SALESMAN  | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 |     30 |
|  7934 | MILLER | CLERK     | 7782 | 1982-01-23 00:00:00 | 1300.00 |    NULL |     10 |
|  7844 | TURNER | SALESMAN  | 7698 | 1981-09-08 00:00:00 | 1500.00 |    0.00 |     30 |
|  7499 | ALLEN  | SALESMAN  | 7698 | 1981-02-20 00:00:00 | 1600.00 |  300.00 |     30 |
|  7782 | CLARK  | MANAGER   | 7839 | 1981-06-09 00:00:00 | 2450.00 |    NULL |     10 |
|  7698 | BLAKE  | MANAGER   | 7839 | 1981-05-01 00:00:00 | 2850.00 |    NULL |     30 |
|  7566 | JONES  | MANAGER   | 7839 | 1981-04-02 00:00:00 | 2975.00 |    NULL |     20 |
|  7788 | SCOTT  | ANALYST   | 7566 | 1982-12-09 00:00:00 | 3000.00 |    NULL |     20 |
|  7902 | FORD   | ANALYST   | 7566 | 1981-12-03 00:00:00 | 3000.00 |    NULL |     20 |
|  7839 | KING   | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 |    NULL |     10 |
+-------+--------+-----------+------+---------------------+---------+---------+--------+
14 rows in set (0.00 sec)

mysql> select * from emp order by  sal desc;
+-------+--------+-----------+------+---------------------+---------+---------+--------+
| empno | ename  | job       | mgr  | hiredate            | sal     | comm    | deptno |
+-------+--------+-----------+------+---------------------+---------+---------+--------+
|  7839 | KING   | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 |    NULL |     10 |
|  7788 | SCOTT  | ANALYST   | 7566 | 1982-12-09 00:00:00 | 3000.00 |    NULL |     20 |
|  7902 | FORD   | ANALYST   | 7566 | 1981-12-03 00:00:00 | 3000.00 |    NULL |     20 |
|  7566 | JONES  | MANAGER   | 7839 | 1981-04-02 00:00:00 | 2975.00 |    NULL |     20 |
|  7698 | BLAKE  | MANAGER   | 7839 | 1981-05-01 00:00:00 | 2850.00 |    NULL |     30 |
|  7782 | CLARK  | MANAGER   | 7839 | 1981-06-09 00:00:00 | 2450.00 |    NULL |     10 |
|  7499 | ALLEN  | SALESMAN  | 7698 | 1981-02-20 00:00:00 | 1600.00 |  300.00 |     30 |
|  7844 | TURNER | SALESMAN  | 7698 | 1981-09-08 00:00:00 | 1500.00 |    0.00 |     30 |
|  7934 | MILLER | CLERK     | 7782 | 1982-01-23 00:00:00 | 1300.00 |    NULL |     10 |
|  7521 | WARD   | SALESMAN  | 7698 | 1981-02-22 00:00:00 | 1250.00 |  500.00 |     30 |
|  7654 | MARTIN | SALESMAN  | 7698 | 1981-09-28 00:00:00 | 1250.00 | 1400.00 |     30 |
|  7876 | ADAMS  | CLERK     | 7788 | 1983-01-12 00:00:00 | 1100.00 |    NULL |     20 |
|  7900 | JAMES  | CLERK     | 7698 | 1981-12-03 00:00:00 |  950.00 |    NULL |     30 |
|  7369 | SMITH  | CLERK     | 7902 | 1980-12-17 00:00:00 |  800.00 |    NULL |     20 |
+-------+--------+-----------+------+---------------------+---------+---------+--------+
14 rows in set (0.00 sec)
总结：
order by排序默认按asc升序来排列
也可指定desc降序排列
3.限制多少行
mysql> select * from emp limit  3;
+-------+-------+----------+------+---------------------+---------+--------+--------+
| empno | ename | job      | mgr  | hiredate            | sal     | comm   | deptno |
+-------+-------+----------+------+---------------------+---------+--------+--------+
|  7369 | SMITH | CLERK    | 7902 | 1980-12-17 00:00:00 |  800.00 |   NULL |     20 |
|  7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 00:00:00 | 1600.00 | 300.00 |     30 |
|  7521 | WARD  | SALESMAN | 7698 | 1981-02-22 00:00:00 | 1250.00 | 500.00 |     30 |
+-------+-------+----------+------+---------------------+---------+--------+--------+
3 rows in set (0.00 sec)

mysql> select * from emp order by  sal desc limit  3;
+-------+-------+-----------+------+---------------------+---------+------+--------+
| empno | ename | job       | mgr  | hiredate            | sal     | comm | deptno |
+-------+-------+-----------+------+---------------------+---------+------+--------+
|  7839 | KING  | PRESIDENT | NULL | 1981-11-17 00:00:00 | 5000.00 | NULL |     10 |
|  7902 | FORD  | ANALYST   | 7566 | 1981-12-03 00:00:00 | 3000.00 | NULL |     20 |
|  7788 | SCOTT | ANALYST   | 7566 | 1982-12-09 00:00:00 | 3000.00 | NULL |     20 |
+-------+-------+-----------+------+---------------------+---------+------+--------+
3 rows in set (0.00 sec)
总结：
limit限定显示前多少行，可与order by联合使用
4.聚合函数
count() sum()函数用法：
#1.各个部门的薪水和
mysql> select deptno,sum(sal) from  emp group by deptno;
+--------+----------+
| deptno | sum(sal) |
+--------+----------+
|     10 |  8750.00 |
|     20 | 10875.00 |
|     30 |  9400.00 |
+--------+----------+
3 rows in set (0.01 sec)

#2.group by字段必须出现在select字段后面   各个部门的各个岗位的薪水和
mysql> select deptno,job, sum(sal) from  emp group by deptno ,job;
+--------+-----------+----------+
| deptno | job       | sum(sal) |
+--------+-----------+----------+
|     10 | CLERK     |  1300.00 |
|     10 | MANAGER   |  2450.00 |
|     10 | PRESIDENT |  5000.00 |
|     20 | ANALYST   |  6000.00 |
|     20 | CLERK     |  1900.00 |
|     20 | MANAGER   |  2975.00 |
|     30 | CLERK     |   950.00 |
|     30 | MANAGER   |  2850.00 |
|     30 | SALESMAN  |  5600.00 |
+--------+-----------+----------+
9 rows in set (0.01 sec)

#3.having    薪水和>5000的各个部门的各个岗位
mysql> select deptno,job,  sum(sal) 
    -> from  emp 
    -> group by deptno ,job
    -> having  sum(sal)>5000; 
+--------+----------+----------+
| deptno | job      | sum(sal) |
+--------+----------+----------+
|     20 | ANALYST  |  6000.00 |
|     30 | SALESMAN |  5600.00 |
+--------+----------+----------+
2 rows in set (0.00 sec)
#4.常用组合where  order  limit 
select deptno,job,  sum(sal) as sum_sal
from  emp 
where job='SALESMAN'
group by deptno ,job
having  sum(sal)>5000 
order by sum(sal) desc 
limit 1;

下面介绍下join及union的用法
数据准备：

create table testa(aid int,aname varchar(40));

create table testb(bid int,bname varchar(40),age int);

insert into testa values(1,'xiaoming');
insert into testa values(2,'LY');
insert into testa values(3,'KUN');
insert into testa values(4,'ZIDONG');
insert into testa values(5,'HB');


insert into testb values(1,'xiaoming',10);
insert into testb values(2,'LY',100);
insert into testb values(3,'KUN',200);
insert into testb values(4,'ZIDONG',110);
insert into testb values(6,'niu',120);
insert into testb values(7,'meng',130);
insert into testb values(8,'mi',170);
5.left join
mysql> select
    -> a.aid,a.aname,
    -> b.bid,b.bname,b.age
    -> from testa as a
    -> left join testb as b on a.aid=b.bid; 
+------+----------+------+----------+------+
| aid  | aname    | bid  | bname    | age  |
+------+----------+------+----------+------+
|    1 | xiaoming |    1 | xiaoming |   10 |
|    2 | LY       |    2 | LY       |  100 |
|    3 | KUN      |    3 | KUN      |  200 |
|    4 | ZIDONG   |    4 | ZIDONG   |  110 |
|    5 | HB       | NULL | NULL     | NULL |
+------+----------+------+----------+------+
5 rows in set (0.00 sec)
总结：
a left join b  a表全，用b表去匹配a表
LEFT JOIN 关键字会从左表 (a) 那里返回所有的行，即使在右表 (b) 中没有匹配的行,匹配不到的列用NULL代替
6.right join
mysql> select
    -> a.aid,a.aname,
    -> b.bid,b.bname,b.age
    -> from testa as a
    -> right join testb as b on a.aid=b.bid;
+------+----------+------+----------+------+
| aid  | aname    | bid  | bname    | age  |
+------+----------+------+----------+------+
|    1 | xiaoming |    1 | xiaoming |   10 |
|    2 | LY       |    2 | LY       |  100 |
|    3 | KUN      |    3 | KUN      |  200 |
|    4 | ZIDONG   |    4 | ZIDONG   |  110 |
| NULL | NULL     |    6 | niu      |  120 |
| NULL | NULL     |    7 | meng     |  130 |
| NULL | NULL     |    8 | mi       |  170 |
+------+----------+------+----------+------+
7 rows in set (0.00 sec)
总结：
a right join b  b表全，用a表去匹配b表
RIGHT JOIN 关键字会右表 (b) 那里返回所有的行，即使在左表 (a) 中没有匹配的行,匹配不到的列用NULL代替
7.inner join
mysql> select
    -> a.aid,a.aname,
    -> b.bid,b.bname,b.age
    -> from testa as a
    -> inner join testb as b on a.aid=b.bid; 
+------+----------+------+----------+------+
| aid  | aname    | bid  | bname    | age  |
+------+----------+------+----------+------+
|    1 | xiaoming |    1 | xiaoming |   10 |
|    2 | LY       |    2 | LY       |  100 |
|    3 | KUN      |    3 | KUN      |  200 |
|    4 | ZIDONG   |    4 | ZIDONG   |  110 |
+------+----------+------+----------+------+
4 rows in set (0.00 sec)

mysql> select
    -> a.aid,a.aname,
    -> b.bid,b.bname,b.age
    -> from testa as a
    -> join testb as b on a.aid=b.bid; 
+------+----------+------+----------+------+
| aid  | aname    | bid  | bname    | age  |
+------+----------+------+----------+------+
|    1 | xiaoming |    1 | xiaoming |   10 |
|    2 | LY       |    2 | LY       |  100 |
|    3 | KUN      |    3 | KUN      |  200 |
|    4 | ZIDONG   |    4 | ZIDONG   |  110 |
+------+----------+------+----------+------+
4 rows in set (0.00 sec)
总结：
inner join 与join 效果一样
在表中存在至少一个匹配时，INNER JOIN 关键字返回行
8.union与union all
mysql> select aid,aname from testa
    -> union
    -> select bid,bname from testb;
+------+----------+
| aid  | aname    |
+------+----------+
|    1 | xiaoming |
|    2 | LY       |
|    3 | KUN      |
|    4 | ZIDONG   |
|    5 | HB       |
|    6 | niu      |
|    7 | meng     |
|    8 | mi       |
+------+----------+
8 rows in set (0.01 sec)

mysql> select aid,aname from testa
    -> union all
    -> select bid,bname from testb;
+------+----------+
| aid  | aname    |
+------+----------+
|    1 | xiaoming |
|    2 | LY       |
|    3 | KUN      |
|    4 | ZIDONG   |
|    5 | HB       |
|    1 | xiaoming |
|    2 | LY       |
|    3 | KUN      |
|    4 | ZIDONG   |
|    6 | niu      |
|    7 | meng     |
|    8 | mi       |
+------+----------+
12 rows in set (0.00 sec)
总结：
union 会去重 union all不去重

mysql emp

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" (然后，你就可以回去等通知了！我们以无符号整型为例，存储范围为0～4294967295，约43亿！我们先说一下，一旦自增id达到最大值，此时数据继续插入是会报一个主键冲突异常如下所示。因此，表中的真实id必然会出现断续的情况。

vivenwan 2020-11-13

MySql索引使用策略分析

(建立索引会占用磁盘空间的索引文件。2.很少数据的列也不应该建立索引,比如 一个性别字段 0或者1,在查询中,结果集的数据占了表中数据行的比例比较大,mysql需要扫描的行数很多,增加索引,并不能提高效率

moyekongling 2020-11-13

mysql 如何动态修改复制过滤器

2、这个rds上有一个本地的ECS只读从库，这个只读从库会实时同步线上的rds数据库中的数据，这个只读从库供业务方查询使用

gloryli 2020-11-12

MySQL ddl语句的使用

数据定义语言create、drop、alter语句 。定义对数据库记录的增、删、改操作。定义对数据库、表、字段、用户的访问权限和安全级别。这小节主要了解下数据定义语言DDL。我们用它对数据库、表进行一些管理操作，比如：建库、删库、建表、修改表、删除表、对字

云中舞步 2020-11-12

MySQL中使用binlog时格式该如何选择

每一条会修改数据的sql都会记录到master的bin-log中。slave在复制的时候sql进程会解析成和原来master端执行过的相同的sql来再次执行。另外就是,由于mysql现在发展比较快，很多的新功能加入，使mysql的复制遇到了不小的挑战,自然

要啥自行车一把梭 2020-11-12

mysql 8.0.22 安装配置图文教程

解压后的目录并没有的my.ini文件，没关系可以自行创建在安装根目录下添加的my.ini ，写入基本配置：。# 允许连接失败的次数。初始化MySQL，在安装时，避免权限问题出错我们尽量使用管理员身份运行CMD，否则在安装时会报错，会导致安装失败的情况，如下

aydh 2020-11-12

解决Navicat Premium 连接 MySQL 8.0 报错\"1251\"的问题分析

人闲太久，努力一下就以为是在拼命。1251 - Client does not support authentication protocol requested by server; consider upgrading MySQL client. My

kuwoyinlehe 2020-11-12

MySQL数据操作-DML语句的使用

DML数据操作语言，是指对数据库进行增删改的操作指令，主要有INSERT、UPDATE、DELETE三种，代表插入、更新与删除，这是学习MySQL必要掌握的基本知识。方语法中 [] 中内容可以省略。值的顺序和表中字段顺序须保持一致。

minerk 2020-11-12

详解 MySQL中count函数的正确使用方法

当搞清楚count函数的运行原理后，相信上面几个问题的答案就会了然于胸。为了解决上述的问题，我创建了一张 user 表，它有两个字段：主键id和name，后者可以为null，建表语句如下。`id` int NOT NULL AUTO_INCREMENT C

vitasfly 2020-11-12

MySQL 基于时间点的快速恢复方案

万幸，这份数据是平台上某些商品的价格，基本上是有限个商品，然后价格值也都是固定的，之前有对这个价格表进行备份，于是给他直接重新导入了一份价格表的数据，这个问题也算是解决了。新建一个实例，全库还原，然后应用备份的binlog，一直去追，追到数据被该坏的时间点

jazywoo在路上 2020-11-11

MySQL外键约束的实例讲解

MySQL的外键约束是用来在两个表之间建立链接的，其中一个表发生变化，另外一个表也发生变化。从这个特点来看，它主要是为了保证表数据的一致性和完整性的。也就是说，只要外键的每个非空值出现在指定的主键中，这个外键的内容就是正确的。

敏敏张 2020-11-11

MySQL用truncate命令快速清空一个数据库中的所有表

用文本编辑器把每条truncate语句前后的“|”替换为空字符，方便后面一次复制多条执行。truncate与drop是DDL语句，执行后无法回滚；delete是DML语句，可回滚。truncate会清空表中的所有行，但表结构及其约束、索引等保持不变；dro

世樹 2020-11-11

修改MySQL8.0 默认的数据目录(快捷操作无配置)

使用场景：我们使用的是阿里云，单独购买了数据盘，MySQL 8.0 数据库默认装在系统盘上，为了考虑安全性和空间问题，我们需要将默认的数据库目录更改到其它位置。操作系统：CentOS 7.6 数据库：MySQL 8.0 查看我本人更多原创文章，请点击

zry 2020-11-11
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