When deleting the MySql database, the client program and the command line controller all reported an error:

ERROR 1010 (HY000): Error dropping database (can't rmdir './db_test', errno: 39)

Solutions:

Go directly to the MySql data directory, directly delete the database corresponding file directory. Then refresh and look at the database, and you will find that the database is gone.

# rm -rf /usr/local/mysql/data/db_test