Question

I would like to know if its possible to create a Postgres function to scan some table rows and create a table that contains WORD and AMOUNT (frequency)? My goal is to use this table to create a Word Cloud.

Answer 1

There is a simple way, but it can be slow (depending on your table size). You can split your text into an array:

SELECT string_to_array(lower(words), ' ') FROM table;

With those arrays, you can use unnest to aggregate them:

WITH words AS (
    SELECT unnest(string_to_array(lower(words), ' ')) AS word
    FROM table
)
SELECT word, count(*) FROM words
GROUP BY word;

This is a simple way of doing that and, has some issues, like, it only split words by space not punctuation marks.

Other, and probably better option, is to use PostgreSQL full text search.