背景

• 获取运行的sql语句，用来排错或者优化查询性能

解决思路

• 开启Mysql的Log功能，那么Mysql的执行语句都会写到Log文件里，然后通过BareTail这个专门查看Log文件的工具即可实时查看mysql生成的语句了

步骤

1. 进入Mysql
2. 启用Log功能(general_log=ON)

• SHOW VARIABLES LIKE "general_log%";
• SET GLOBAL general_log = 'ON';

3. general_log_file 字段展示的是sql语句保存路径
4. 假如你想设置Log文件地址(所有Sql语句都会在general_log_file里)

• SET GLOBAL general_log_file = 'c:\mysql.log';

5. 假如想关闭sql语句打印

• SET GLOBAL general_log = 'OFF';

代码示范

mysql> SHOW VARIABLES LIKE "general_log%"; 
+------------------+----------------------------------+
| Variable_name    | Value                            |
+------------------+----------------------------------+
| general_log      | OFF                              |
| general_log_file | /var/lib/mysql/ubuntu-xenial.log |
+------------------+----------------------------------+
2 rows in set (0.01 sec)

mysql> SET GLOBAL general_log = 'ON';
Query OK, 0 rows affected (0.01 sec)

mysql> SHOW VARIABLES LIKE "general_log%";
+------------------+----------------------------------+
| Variable_name    | Value                            |
+------------------+----------------------------------+
| general_log      | ON                               |
| general_log_file | /var/lib/mysql/ubuntu-xenial.log |
+------------------+----------------------------------+
2 rows in set (0.00 sec)

mysql> 

可以下载BareTail专门查看Log文件的绿色软件(提供免费版本仅220k)，看sql语句会更友好