create index with cast

[jennyflower]

Hi, I was just wondering if I am able to do someting like this:

CREATE INDEX v_cust_no ON order_header USING btree ((h_cust_no::integer));

Or this:

CREATE INDEX l_unique ON order_line_item USING btree ((text(l_order_no) || text(l_item_no)));

in MySQL.

Thanks