The mysql modification case in docker does not take effect

1. First of all my docker and MySQL version is as follows:
   
2. According to the methods on the Internet, I tried to modify the configuration file, or change the docker MySQL command lower_case_table_names=1, but unfortunately, show global variables like '%lower_case%';it did not take effect after I started MySQL, and lower_case_table_names is still 0.
3. Later, I checked through the official documents and found the solution. The official website stated that the method in 2 only works when docker run mysql is executed for the first time, so I back up the database and empty the data (- ./ mysql/data:/var/lib/mysql) and put the following configuration file up. This time, restart mysql.