The Wongwian Yai Market in Bangkok is a small market and a bit average when compared to others. The market has lots to offer but is much smaller than other markets such as the market in China Town or the Chatuchak Weekend Market outside of Bangkok.
Restaurants in the market are more than reasonably priced and they do offer a variety of seafood as well as fresh produce. It is best to either use the BTS subway system if you are going in the afternoon as the traffic jams in this area picks up in the late afternoon. The market is far from Central Bangkok as Wongwianyai is a part of what is called the old town of Bangkok.