1.Mysql has been installed and DB driver has been installed successfully. Failed when trying to connect to the database

ERROR 2002 (HY000)Can"t connect to local MySQL server through socket "/tmp/mysql.sock" (2)

tried:

mysql start

ERROR 2002 (HY000): Can"t connect to local MySQL server through socket"/ tmp/mysql.sock" (2)

mysql -uroot

ERROR 2002 (HY000): Can"t connect to local MySQL server through socket"/ tmp/mysql.sock" (2)

mysql -h localhost

ERROR 2002 (HY000): Can"t connect to local MySQL server through socket"/ tmp/mysql.sock" (2)

mysql -h 127.0.0.1

ERROR 2003 (HY000): Can"t connect to MySQL server on "127.0.0.1" (61)
then go to the temp folder where there is no target file at all

/tmp/mysql.sock

use the find command:

find / -name mysql.sock

both:

Permission denied

many people failed to find it on the Internet. Thank you