PostgreSQL

Como listar todas as tabelas do banco

SELECT 
    *
FROM
    pg_catalog.pg_tables
WHERE
    schemaname != 'pg_catalog'
    AND schemaname != 'information_schema'
;

Como apagar todas as tabelas do banco ⚠️

DROP SCHEMA public CASCADE;
CREATE SCHEMA public;

Remover todos caracteres que não são letras

regexp_replace(value, '[^A-z ]+', '', 'g')

Row-Level permission

https://www.postgresql.org/docs/current/ddl-rowsecurity.html
https://www.enterprisedb.com/postgres-tutorials/how-implement-column-and-row-level-security-postgresql

Criar uma função PL/pgSQL

CREATE OR REPLACE FUNCTION even_odds(max int)
 RETURNS int[][]
 LANGUAGE plpgsql
AS $function$
DECLARE
    evens int[] := Array[]::int[];
    odds int[] := Array[]::int[];
BEGIN
    FOR n IN 1..max loop
        IF n % 2 = 0 then
            evens := ARRAY_APPEND(evens, n);
        ELSE
            odds := ARRAY_APPEND(odds, n);
        END IF;
    END LOOP;

    RETURN Array[evens, odds];
END;
$function$
;

SELECT even_odds(100);