How to format booleans using psql? - psql

Question

Using psql, I would like to format boolean values to display as TRUE and FALSE instead of t and f by default, as I find the latter difficult to distinguish from one another.
I can change how null displays by setting the following in my ~/.psqlrc:
\pset null 'Ø'
How can I do so for boolean values?

Answer 1

While there doesn't appear to be a simple way to modify the psql output behavior like for the null separator, you may achieve this another way, by modifying the output value, casting it to text.
Given a schema like:
CREATE TABLE bools (
name text,
alive boolean
);
INSERT INTO bools VALUES ('Taylor Swift', TRUE);
INSERT INTO bools VALUES ('Elvis Presley', FALSE);
We can then query for the boolean values, case them along the way, or even create a function that handles the casting for us:
postgres=# SELECT name, alive FROM bools;
name | alive
---------------+-------
Taylor Swift | t
Elvis Presley | f
(2 rows)
postgres=# SELECT name, alive::text FROM bools;
name | alive
---------------+-------
Taylor Swift | true
Elvis Presley | false
(2 rows)
postgres=# SELECT name, UPPER(alive::text) AS alive FROM bools;
name | alive
---------------+-------
Taylor Swift | TRUE
Elvis Presley | FALSE
(2 rows)
postgres=# CREATE FUNCTION bool_to_upper(boolean) RETURNS text
postgres-# AS $$ SELECT UPPER(CAST($1 AS text)) $$
postgres-# LANGUAGE SQL;
CREATE FUNCTION
postgres=# SELECT name, bool_to_upper(alive) AS alive FROM bools;
name | alive
---------------+-------
Taylor Swift | TRUE
Elvis Presley | FALSE
(2 rows)
See this SQLfiddle for a working example on Postgresql 9.6.

Answer 2

There aren't any settings which allow you to format boolean output like that, but Marko Tikkaja published a patch a few years ago to support this.