Table 1: Schema for the bookworm database. Primary keys are underlined. There are some foreign key references to link the tables together; you can make use of these with natural joins.

```
Author(aid, alastname, afirstname, acountry, aborn, adied).
Book(bid, btitle, pid, bdate, bpages, bprice).
City(cid, cname, cstate, ccountry).
Publisher(pid, pname).
Author_Book(aid, bid).
Publisher_City(pid, cid).

```

I need to reduce the prices of all of Charles Dickens’s books by 20 percent, using only one update statement.

Tried using...

```
update book
set bprice=bprice * .2
where alastname = 'Dickens';

```

but no luck, I get the syntax:

```
ERROR:  column "alastname" does not exist
LINE 3: where alastname = 'Dickens';

```

Not sure how to use subselects or 'nested select queries' to find the primary keys of the tuples that I need to update.