Reddit mentions of Studio Ghibli:Chopin de GHIBLI Piano Solo Sheet Music Book/Advanced/difficult

If you like Chopin (playing ballade in g minor? :-) this could be interesting for you:
https://www.amazon.com/Studio-Ghibli-Chopin-Advanced-difficult/dp/4636840011

You can hear the full album on youtube, too.

EDIT: Browse on this website, they publish most of Ghibli piano sheets:

http://www.wasabisheetmusic.com/product-list/96

While people are giving good suggestions, they're posting links to sites that overcharge. Unless you have reasons to hate Amazon, Amazon Japan sells pretty much everything that's been mentioned with zero markup and very low shipping costs.

For example, the one from japancoolbooks costs only $26.82 on Amazon.jp, shipped to California (it'll arrive in 2-3 days). If you order multiple books at once, you'll save even more.

Japan has a relatively large percentage of population that play the piano well, and from my experience, has more high quality piano arrangements for all sorts of music (including Western pop music) than the US does.

Edit: Added links to some of the books mentioned here:

Studio Ghibli Collection Easy Piano Solo Sheet Music

Joe Hisaishi Piano Collection

Ghibli Best Stories

Chopin de Ghibli

Hayao Mizayaki & Studio Ghibli Best Album

Also, I'm assuming the OP can read kanji or 漢字, since zhulin is a Chinese name. Just search for "上級 宮崎駿 ピアノ", which translates into "advanced hayao miyazaki piano".