Using Google Natural Language API from PL/Python. Make sure to set up authentication and install the proper libraries to the PL/Python PYTHONPATH first.

fun.sql

CREATE EXTENSION plpython3u;
CREATE TYPE GOOGSENTIMENTRESULT AS (
  sentiment FLOAT,
  magnitude FLOAT
);
CREATE OR REPLACE FUNCTION GOOGsentiment(txt TEXT)
  RETURNS GOOGSENTIMENTRESULT
AS $$
# Imports the Google Cloud client library
from google.cloud import language

# Instantiates a client
language_client = language.Client()
document = language_client.document_from_text(txt)

# Detects the sentiment of the text
sentiment = document.analyze_sentiment().sentiment

return { "sentiment": sentiment.score, "magnitude": sentiment.magnitude }

$$ LANGUAGE plpython3u;

 -- Usage:
SELECT GOOGsentiment('hello there, friend! It sure is a great day, eh?');

 -- Example, use it directly with your data:
SELECT DISTINCT ON (response) GOOGsentiment(response), response
FROM your_table_with_responses
WHERE LENGTH(response) > 200
ORDER BY response;