MySQL root密碼正確，卻無法從本地登錄MySQL

本文有許多廢話，可以直接跳到分割線

補上周的博客，這個是最近遇到的坑，mac  brew安裝的mysql5.6 剛開始是正常的    但是 某天 我mysql root突然登錄不上了  我覺得密碼應該是正確的

報錯圖忘記截了(以后要記得遇到問題截圖 寫博客用)  報錯內容如下(注意報錯信息 )

 

1 ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES);

 

好的，登錄不上 咋辦  改root密碼唄，首先要跳過密碼認證skip-grant-tables  那么要找到mysql的配置文件，然后我發現mac安裝mysql 在etc下根本沒有my.cnf 后來發現在下列目錄中有個默認配置文件，進去看了里面的內容，感覺配置項有點少 我就自建了my.cnf文件，網上找了配置復制下來（這個默認的也能用，不過我沒試過，如果要用就拷到etc下改為my.cnf 然后配置一下就好了）

/usr/local/opt/mysql\@5.6/support-files/my-default.cnf

　　

 

 

 

網上找的 my.cnf的配置  在etc下新建my.cnf然后復制進去就行了

    # Example MySQL config file for medium systems.

    #

    # This is for a system with little memory (32M - 64M) where MySQL plays

    # an important part, or systems up to 128M where MySQL is used together with

    # other programs (such as a web server)

    #

    # MySQL programs look for option files in a set of

    # locations which depend on the deployment platform.

    # You can copy this option file to one of those

    # locations. For information about these locations, see:

    # http://dev.mysql.com/doc/mysql/en/option-files.html

    #

    # In this file, you can use all long options that a program supports.

    # If you want to know which options a program supports, run the program

    # with the "--help" option.

    # The following options will be passed to all MySQL clients

    [client]

    default-character-set=utf8

    #password = your_password

    port = 3306

    socket = /tmp/mysql.sock

    # Here follows entries for some specific programs

    # The MySQL server

    [mysqld]
    # skip

    character-set-server=utf8

    init_connect='SET NAMES utf8

    port = 3306

    socket = /tmp/mysql.sock

    skip-external-locking

    key_buffer_size = 16M

    max_allowed_packet = 1M

    table_open_cache = 64

    sort_buffer_size = 512K

    net_buffer_length = 8K

    read_buffer_size = 256K

    read_rnd_buffer_size = 512K

    myisam_sort_buffer_size = 8M

    character-set-server=utf8

    init_connect='SET NAMES utf8'

# Don't listen on a TCP/IP port at all. This can be a security enhancement,

# if all processes that need to connect to mysqld run on the same host.

# All interaction with mysqld must be made via Unix sockets or named pipes.

# Note that using this option without enabling named pipes on Windows

# (via the "enable-named-pipe" option) will render mysqld useless!

#

#skip-networking



    # Replication Master Server (default)

    # binary logging is required for replication l

    og-bin=mysql-bin



        # binary logging format - mixed recommended

        binlog_format=mixed



            # required unique id between 1 and 2^32 - 1

            # defaults to 1 if master-host is not set

            # but will not function as a master if omitted

            server-id = 1



        # Replication Slave (comment out master section to use this)

        #

        # To configure this host as a replication slave, you can choose between

        # two methods :

        #

        # 1) Use the CHANGE MASTER TO command (fully described in our manual) -

        # the syntax is:

        #

        # CHANGE MASTER TO MASTER_HOST=<host>, MASTER_PORT=<port>,

        # MASTER_USER=<user>, MASTER_PASSWORD=<password> ;

        #

        # where you replace <host>, <user>, <password> by quoted strings and

        # <port> by the master's port number (3306 by default).

        #

        # Example:

        #

        # CHANGE MASTER TO MASTER_HOST='125.564.12.1', MASTER_PORT=3306,

        # MASTER_USER='joe', MASTER_PASSWORD='secret';

        #

        #OR

        #

        # 2) Set the variables below. However, in case you choose this method, then

        # start replication for the first time (even unsuccessfully, for example

        # if you mistyped the password in master-password and the slave fails to

        # connect), the slave will create a master.info file, and any later

        # change in this file to the variables' values below will be ignored and

        # overridden by the content of the master.info file, unless you shutdown

        # the slave server, delete master.info and restart the slaver server.

        # For that reason, you may want to leave the lines below untouched

        # (commented) and instead use CHANGE MASTER TO (see above)

        #

        # required unique id between 2 and 2^32 - 1

        # (and different from the master)

        # defaults to 2 if master-host is set

        # but will not function as a slave if omitted

        # server-id = 2

        #

        # The replication master for this slave - required

        #master-host = <hostname>

        #

        # The username the slave will use for authentication when connecting

        # to the master - required

        #master-user = <username>

        #

        # The password the slave will authenticate with when connecting to

        # the master - required

        #master-password = <password>

        #

        # The port the master is listening on.

        # optional - defaults to 3306

        #master-port = <port>

        #

        # binary logging - not required for slaves, but recommended

        #log-bin=mysql-bin



            # Uncomment the following if you are using InnoDB tables

            #innodb_data_home_dir = /usr/local/mysql/data

            #innodb_data_file_path = ibdata1:10M:autoextend

            #innodb_log_group_home_dir = /usr/local/mysql/data

            # You can set .._buffer_pool_size up to 50 - 80 %

            # of RAM but beware of setting memory usage too high

            #innodb_buffer_pool_size = 16M

            #innodb_additional_mem_pool_size = 2M

            # Set .._log_file_size to 25 % of buffer pool size

            #innodb_log_file_size = 5M

            #innodb_log_buffer_size = 8M

            #innodb_flush_log_at_trx_commit = 1

            #innodb_lock_wait_timeout = 50

                [mysqldump]

                quick

                max_allowed_packet = 16M



                    [mysql]

                    no-auto-rehash

                    # Remove the next comment character if you are not familiar with SQL

                    #safe-updates

                    default-character-set=utf8

                [myisamchk]

                key_buffer_size = 20M

                sort_buffer_size = 20M

                read_buffer = 2M

                write_buffer = 2M

                    [mysqlhotcopy]

                    interactive-timeout

 

然后在[mysqld]下 加入划紅線的  （不用了就#號注釋掉）

 

 

OK 然后mysql -uroot -p  登錄數據庫 不需要密碼直接回車  

 

mysql> use mysql;  

 
# 改密碼 新版本數據庫需要把左邊的password改成authentication_string 
mysql> update user set password=password('123') where user='root' and host='localhost';  

 
# 刷新權限
mysql> flush privileges; 

# 退出
mysql> exit

 

之后進my.cnf  將跳過密碼的skip-grant-tables 注釋掉 退出，mysql -uroot -p  輸入密碼  還是報錯，，， 好吧 那咋辦呢，繼續查唄

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                                                                                                              手動分割線

 

然后看到幾個博客里說不能本地登錄可能是localhost沒有和host對應，那么看看唄，重復上面步驟，跳過密碼登錄（否則無密碼游客登錄是看不到mysql庫的）

mysql> use mysql

Database changed

mysql> select user,host,password from user where user='root';

 (無圖，干說借助下圖腦補)

我發現 host 這一欄沒有對應 localhost 而是變成了我虛擬機的NAT映射的那個ip （這個真是坑）而host中 有127.0.0.1 那也就是說 通過mysql -uroot -p123 -h127.0.0.1 是可以登錄的 

 

那么解決問題也就很簡單了

update user set host='localhost' where user='root' and host='我之前NAT映射的ip';

或者

insert into user(user,host) values('root',localhost);

 

 再看

select user,host,password from user where user='root';

記得刷新權限 

flush privileges;

 

 

 

 

然后退出 回配置文件 注釋掉skip-grant-tables

 

mysql -uroot -p

password:

 

 

 

 

oK！