SQL Update Query To Copy Data

I'm a bit of a newby to creating update queries so I was hoping those more
experienced could help with what should be a simple query. I do know to
create backups and test on a test database first.

I need to copy an items' cost from location 'CA' to the cost in location
'OH' when the cost in 'CA' is not zero
Table name is ITEMS
Location column is LOC
Cost column is COST

Here's the Select statement from Enterprise Manager's Open Table, Query tool

SELECT loc AS Expr1, cost AS Expr2
FROM ITEMS
WHERE (loc = 'CA') AND (cost <> 0)


I just can't seem to get this into a working Update query.

Thanks in advance...