pandas join two dataframe for each column with one column from other code example

Example 1: pandas merge two columns from different dataframes

#suppose you have two dataframes df1 and df2, and 
#you need to merge them along the column id
df_merge_col = pd.merge(df1, df2, on='id')

Example 2: how to join two dataframe in pandas based on two column

merged_df = left_df.merge(right_df, how='inner', left_on=["A", "B"], right_on=["A2","B2"])