最近準備學習web項目需要用到數據庫，正好之前用公司的電腦裝過MySQL，試了一下發現mysql本機用localhost 能連接，但是其他機器用IP卻連接不上，在網上看了一下解決方案入下：
navicat連接數據庫錯誤提示：1045-Access denied for user ‘root’@‘localhost’（using password: YES）
原因：可能有以下原因
1.root帳戶默認不開放遠程訪問權限
2.密碼錯誤
解決方案：
開放mysql的訪問
- 用命令後方式進入MySQL ；Linux是用命令：mysql -u root -p （如果本機都無法進入mysql則說明是密碼錯誤,查看第二步）
- 輸入密碼在Enter password:
******（自己的密碼） - 打開 mysql 數據庫：
use mysql(因爲MySQL的權限存儲在這個裏面) - 將user='root'的用戶訪問權限爲all：
update user set host='%' where user='root'; - 讓賦予的權限立即生效：
flush privileges
完整流程入下：
[root@VM_0_4_centos ~]# mysql -u root -p
Enter password: ******
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 8.0.15 MySQL Community Server - GPL
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use mysql
Database changed
mysql> update user set host='%' where host= 'localhost';
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0
mysql> select host,user from user;
+------+------------------+
| host | user |
+------+------------------+
| % | mysql.infoschema |
| % | mysql.session |
| % | mysql.sys |
| % | root |
+------+------------------+
4 rows in set (0.00 sec)
mysql> flush privileges ;
Query OK, 0 rows affected (0.01 sec)
注意最後一步如果沒執行可能會導致修改後成功但還是訪問不了
如果確認以上操作完成了，還是拒絕訪問
則嘗試修改MySQL密碼：
2.密碼錯誤
[root@VM_0_4_centos ~]# vim /etc/my.cnf ## 編輯my.cnf 文件，設置免密登陸
[root@VM_0_4_centos ~]# cat /etc/my.cnf
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
# skip-grant-tables # 跳過權限驗證 (登陸時不需要密碼）
max_allowed_packet=20M #server接受的數據包大小 解決錯誤： django.db.utils.InternalError: (1153, "Got a packet bigger than 'max_allowed_packet' bytes")
[root@VM_0_4_centos ~]# service mysqld restart # 重啓服務
Redirecting to /bin/systemctl restart mysqld.service
[root@VM_0_4_centos ~]# mysql -u root -p # 進入MySQL
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.28 MySQL Community Server (GPL)
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use mysql; # 進入 mysql庫
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
mysql> update user set authentication_string=password('123456') where user='root'; #更新密碼
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1 Changed: 1 Warnings: 1
mysql> flush privileges; # 刷新權限
Query OK, 0 rows affected (0.00 sec)
#重新編輯 my.cnf 文件，取消密碼登陸。然後重啓服務