MySQL: самые нужные мне команды

To login (from unix shell) use -h only if needed.
# [mysql dir]/bin/mysql -h hostname -u root -p

Create a database on the sql server.
mysql> create database [databasename];

List all databases on the sql server.
mysql> show databases;

Switch to a database.
mysql> use [db name];

To see all the tables in the db.
mysql> show tables;

To see database’s field formats.
mysql> describe [table name];

To delete a db.
mysql> drop database [database name];

To delete a table.
mysql> drop table [table name];

Show all data in a table.
mysql> SELECT * FROM [table name];

Returns the columns and column information pertaining to the designated table.
mysql> show columns from [table name];

Show certain selected rows with the value «whatever».
mysql> SELECT * FROM [table name] WHERE [field name] = "whatever";

Count rows in table.
mysql> SELECT COUNT(*) FROM pet;

Count rows in table and group by some field.
mysql> SELECT owner, COUNT(*) FROM pet GROUP BY owner;

Источники:
http://www.pantz.org/software/mysql/mysqlcommands.html
http://dev.mysql.com/doc/refman/5.1/en/counting-rows.html