Sentiment analysis is a relatively new field of study at the intersection of computer science and linguistics that aims to find an opinion expressed in a text. It has received a swell of interest in both academia and industry. This paper provides an overview of the basic approaches for sentiment analysis task: machine learning-based approach and lexicon-based approach. The machine learning approach is based on training models on corpora annotated with polarity information and the lexicon-based approach is based on using sentiment lexicon. Recently, a hybrid approach is employed to leverage the strength of both two approaches'