How do I specify na_values in pandas using read_sql?

Question

I'm trying to create a pandas dataframe from a sql table. I read in the data using data=pd.read_sql(query,con=con), and this works just fine. However, I wish to set which type of elements in the data frame is NaN. When reading a csv, this can be set using pd.read_csv('file.csv',na_values=['',[]']). Is there a similar flag available using read_sql?

Answer 1

There is no such parameter because pandas/numpy NaN corresponds NULL (in the database), so there is one to one relation.

But if you want to replace other values with NaNs you can do it this way:

df = df.replace(['', 'null'], [np.nan, np.nan])