MySQL导出文件遇到secure-file-priv报错
前两天在电脑上安装了MySQL 8.0.18，在尝试从数据库导出csv文件时，遇到了以下报错：
ERROR 1290 (HY000): The MySQL server is running with the --secure-file-priv option so it cannot execute this statement
secure-file-priv资料查询
上网一搜发现报错原因和secure-file-priv的值有关，secure-file-priv参数是用来限制mysql导入导出到哪个目录的。
查阅官方文档找到secure-file-priv的值有以下几种情况：
secure-file-priv取值
而使用命令 show variables like "%secu%"; 检查secure-file-priv的值，发现本地secure_file_priv的值设置的是NULL，那么就需要将secure_file_priv的值设置为空字符串或者dirname才能导出文件。
屏幕快照 2019-10-31 22.12.50.png
解决办法
那么接着问题来了，在哪里设置secure-file-priv的值呢？
不能直接设置，必须要在my.cnf文件里设置(mac在my.cnf)。
那么my.cnf文件在哪里呢？
在下面3个关键目录中使用find命令全部搜了一遍也没有找到my.cnf文件，没有办法只有在网上重新找了一个my.cnf文件。
/etc
/usr/local/mysql/support-files
/usr/local/mysql-8.0.18-macos10.14-x86_64/support-files
在找到my.cnf后，进入/etc目录下，使用sudo vim my.cnf命令新建my.cnf文件，并将以下内容添加到my.cnf文件中。
# 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]
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'
secure_file_priv=''
# 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
log-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
注意！！！
一定要把上面文本中的password = your_password修改成自己的MySQL数据库的密码，我就是忘记改了，搞了3天，不管怎么修改secure_file_priv=''，在重启数据库都没有用，终于在第3天重新梳理了一遍流程，仔细研究了my.cnf文件后，发现了问题所在。
修改好后，在系统偏好设置的MySQL中配置Configuration File文件，重新Apply然后再重启MySQL服务就可以了。
屏幕快照 2019-10-31 23.33.50.png
见证奇迹的时刻
一切准备就绪，让我们重新再来导出一次user表
mysql> select * from user into outfile '/tmp/user.csv';
Query OK, 4 rows affected (0.00 sec)
大功告成！
补充
虽然secure_file_priv设置为空字符串，也就是说可以任意导入导出到任何文件目录下，但是我也试了桌面和etc文件夹，都导出失败了，上网查询原因可能与文件访问权限、文件分组有关，这里就不再详细讨论了，/tmp目录是可以导入导出的，大家可以在这个目录下导出csv文件。
mysql> select * from user into outfile '~/Desktop/user/user.csv';
ERROR 1 (HY000): Can't create/write to file '/var/empty/Desktop/user/user.csv' (OS errno 2 - No such file or directory)
mysql> select * from user into outfile '/etc/user.csv';
ERROR 1 (HY000): Can't create/write to file '/etc/user.csv' (OS errno 13 - Permission denied)
参考文章：
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