Introduction to SQL
PLEASE NOTE: This tutorial comes from my FREE video course called SQL Boot Camp.
-- Connect using psql, execute a SELECT and create a test database
select 'Hello World!';
create database test;
-- Connect using psql to the test database
-- psql test
create table posts (
id integer,
title character varying(100),
content text,
published_at timestamp without time zone
);
insert into posts (id, title, content, published_at) values (100, 'Intro to SQL', 'Epic SQL Content', '2018-01-01');
insert into posts (id, title, content, published_at) values (101, 'Intro to PostgreSQL', 'PostgreSQL is awesome!', now());
insert into posts (id, title, content) values (102, 'Intro to SQL Where Clause', 'Easy as pie!');
-- Retrieve all columns from all posts
select * from posts;
-- Retrieve specific columns
select title from posts;
select title as header from posts;
-- Use aggregate function
select count(*) from posts;
-- Filter rows returned
select * from posts where id = 101;
-- Order rows returned
select * from posts order by title;
-- Putting it all together
select *
from posts
where published_at > '2018-02-01'
order by title;
Please go ahead and leave a comment below if you have any questions about this tutorial.