How can I select just the first X characters from a text column

Question

On my PostgreSQL DB I have a table that looks like below. The description column can store a string of any size.

What I'm looking for, is a way to select just the first X chars from the content of the description column, or the whole string if X > description.length

CREATE TABLE descriptions (
    id uuid NOT NULL,
    description text NULL,
);

E.g.: If X = 100 chars and if in the description column I store a string containing 150+ chars, when I run select <some method on description> from descriptions, I just want to get back the first 100 chars from the description column.

Bonus if the approach proposed is extremely fast!

Answer 1

Use a type cast or use substring():

SELECT CAST(description AS varchar(100)), substring(description for 100)
FROM descriptions;

Or if you want to do it the "PostgreSQL way":

SELECT description::varchar(100), substr(description, 1, 100)
FROM descriptions;