MySQL commands I learned today.

• alter table [tablename] add [columnname] varchar (20); Add a new column to a table.
• alter table [tablename] drop [columnname]; Delete a column from a table.
• alter table [tablename] change [columnname] [newcolumnname] varchar (20); Change a column name and size.
• alter table [tablename] rename [newtablename]; Change a name of a table.
• mysql -u [username] -p [databasename] < hoge.sql; Load an external sql file.
• mysqldump -u [username] -p [databasename] > moge.sql; Dump a database to an external file.