一、业务场景

在mac环境下，由于通过SQL查询，使用到了group by，而且by多个字段。例如：select a,b,c from table group by a,b 。发现执行SQL报错了。

Expression #5 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'table.a' 
which is not functionally dependent on columns in GROUP BY clause; 

二、修改sql_mode

2.1、进入mysql，查看sql_mode

mysql -u root -p
-bash: mysql: command not found

2.1.1、解决mysql: command not found问题

造成问题的原因是，路径变量$PATH没有指定mysql的安装路径。

1、首先新建文件bash_profile，并且指定mysql的安装路径

cd ~
touch .bash_profile
open -e .bash_profile

2、在bash_profile中追加配置

export PATH=$PATH:/usr/local/mysql/bin

3、退出保存后，生效配置

source ~/.bash_profile

4、重新进入mysql命令行

2.2、查看sql_mode

select @@sql_mode\G

发现配置是“ONLY_FULL_GROUP_BY“,修改配置。

2.3、修改sql_mode配置

set @@sql_mode 
='STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION';

2.4、再次查看sql_mode

自以为好了，在命令行中手动执行相关SQL，真的可以通过。然后再一次去执行代码，发现还是同样的错误和报错，那么再一次进入mysql命令界面，，查看sql_mode，发现配置回去了。所以当时修改的只是当时回话的效果，全局生效的话，还得修改mysql 的配置文件my.cnf。

三、修改my.cnf配置

3.1、查找my.cnf

cd /etc

发现配置文件不存在

3.1.1、新建配置

1、先看MAC的mysql目录下是否存在默认的配置文件

cd /usr/local/MySQL/support-files/
ll

发现没有默认的default配置文件，则新建配置

2、进入/ect新建my.cnf

# 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' 
# 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

然后在[mysqld]栏下追加如下

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

3.2、保存、赋予权限

注意点，这个时候不能赋予太高的权限，如果权限太高，mysql认为不安全，就会发生如下提示：

Warning: World-writable config file '/etc/my.cnf' is ignored

则需要重新赋予权限即可

 chmod 644 /etc/my.cnf

四、重启mysql服务

重启命令均在 /usr/local/mysql/support-files/目录下

sudo /usr/local/mysql/support-files/mysql.server restart

这下就真的可以重新发起接口的调用了。

完！