Here will be some commands and their examples with explanations.

• create DB:
  CREATE DATABASE `my_db` CHARACTER SET utf8 COLLATE utf8_general_ci;
• show db collection and charset:
  USE db_name;
SELECT @@character_set_database, @@collation_database;
• create user:
  CREATE USER 'jeffrey'@'localhost' IDENTIFIED BY 'mypass';
• grant permissions to some db:
  GRANT ALL PRIVILEGES ON 'DB_name'.* TO 'monty'@'localhost';
• show processlist (who’s connected and if they’re currently running anything):
  SELECT * FROM information_schema.processlist \G
show processlist;
• enable queue loggining:
  SET global log_output='table';
SET global general_log=1;
• enable slow logs:
  SET global long_query_time=2;
SET global slow_query_log=1;
• mysql skipp counter and restart replication;
  STOP slave;
SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;
START slave;
show slave status \G
• enable mysql profiling:
  set profiling=1;
query;
show profiles;
show profile for query qry_number;
set profiling=0;
• skip specific error in replication. Add below to my.cnf:
  slave_skip_errors error_number
• log-slave-updates
  innodb_flush_log_at_trx_commit=2 (default = 1)
innodb_flush_method=O_DIRECT
• create mysql replication:
  GRANT replication slave ON *.* TO "repl_user"@"%" IDENTIFIED BY "password";
CHANGE MASTER TO MASTER_HOST='master_host_fqdn', master_user='repl_user', MASTER_PASSWORD='password', MASTER_LOG_FILE='binlog_file_name', MASTER_LOG_POS=pos_number;
• Enable read-only mode:
  SET GLOBAL read_only = ON;
  or add to /etc/mysql/my.cnf: read_only=1
• change column type in table:
  ALTER TABLE table_name MODIFY column_name type;
• add column to table:
  ALTER TABLE table_name ADD column_name type;
• Change user password:
  ALTER USER some_user@'%' IDENTIFIED BY 'new_password';
• compare databases between servers (also available for the same server):
  mysqldbcompare --server1=root@localhost:3306 --server2=root:pwd@mysql_url:3306 --changes-for=server2
  –changes-for – means show changes for server. I.e. above should be compared with server1