mysql-index multiple index multi index

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

CREATE INDEX TEMP0127 ON DNOTE_LINE (QTY);

ALTER TABLE DNOTE_LINE DROP INDEX TEMP0127;

create index idx on t1 (accountid, logindate);

 multiple index

create index orderid_productid on orders(order_id, product_id)

http://www.ovaistariq.net/17/mysql-indexes-multi-column-indexes-and-order-of-columns/