Syntax:
CREATE [UNIQUE|FULLTEXT|SPATIAL] INDEX index_name
    [index_type]
    ON tbl_name (index_col_name,...)

index_col_name:
    col_name [(length)] [ASC | DESC]

index_type:
    USING {BTREE | HASH}

CREATE INDEX is mapped to an ALTER TABLE statement to create indexes.
See [HELP ALTER TABLE]. CREATE INDEX cannot be used to create a PRIMARY
KEY; use ALTER TABLE instead. For more information about indexes, see
http://dev.mysql.com/doc/refman/5.0/en/mysql-indexes.html.

URL: http://dev.mysql.com/doc/refman/5.0/en/create-index.html

