PostgreSQL Tutorial

PostgreSQL is a free and open-source database management system used to store, organize and manage data efficiently. It is one of the most popular databases because it is reliable, secure and can handle large amounts of data.

• Supports SQL queries to store, retrieve and manage data.
• Allows transactions to keep data accurate and consistent.
• Supports JSON and JSONB data for modern applications.
• Uses Multi-Version Concurrency Control (MVCC) to allow many users to work with the database at the same time.
• Can be extended with custom data types, functions and extensions.

Note: Before learning PostgreSQL, it is recommended to have basic knowledge of SQL concepts.

Writing Your First SQL Query in PostgreSQL

Below is an example to display “Hello, World!” using SQL:

1. Create a database

CREATE DATABASE test_db;

2. Connect to the database

\c test_db;

3. Create a table

CREATE TABLE greetings (
 id SERIAL PRIMARY KEY,
 message VARCHAR(255)
);

4. Insert a message

INSERT INTO greetings (message)
VALUES ('Hello, World!');

5. Retrieve the message

SELECT message FROM greetings;

Output

PostgreSQL Basics

Learn the fundamental concepts of PostgreSQL, including installation, setup and the basic building blocks needed to work with databases.

• Introduction
• Installl PostgreSQL
• Loading a Database
• Data Types
• MySQL vs. PostgreSQL

Database Management

Databases help organize and store data. This section covers the essential operations used to manage databases in PostgreSQL.

• CREATE
• SHOW
• ALTER
• RENAME
• DROP

Table Management

Tables are used to store data in rows and columns. This section explains how to create and manage tables effectively.

• CREATE
• ALTER
• DROP
• TRUNCATE

Querying & Filtering Data

Learn how to retrieve, filter, sort and analyze data using PostgreSQL queries.

• SELECT
• WHERE
• ORDER BY
• GROUP BY
• HAVING
• LIMIT
• IN
• IS NULL
• LIKE
• NOT LIKE
• BETWEEN

Set Operators

Set operators help combine or compare the results of multiple queries.

• Union 
• Intersect
• Except

Subqueries

Subqueries in PostgreSQL allow queries to be nested inside another query, making it easier to perform complex filtering and data retrieval operations.

• Introduction
• EXISTS
• ANY
• ALL

Modifying Data

Data modification in PostgreSQL helps insert new records, update existing data, delete rows and perform upsert operations efficiently.

• INSERT
• UPDATE
• DELETE
• UPSERT

Conditionals & Control Flow

Conditional and control statements in PostgreSQL help manage decision-making, looping and logical operations within queries and procedural code.

• CASE
• COALESCE
• NULLIF()
• CAST
• IF Statement
• Loop Statement
• While Loops
• For Loops
• Exit
• Continue

Constraints

Constraints in PostgreSQL ensure data accuracy and integrity by restricting invalid or duplicate data from being stored in tables.

• Primary Key
• Foreign Key
• CHECK Constraint
• UNIQUE Constraint
• NOT NULL Constraint

JOINS & Schemas

Joins in PostgreSQL combine data from multiple tables, while schemas help organize and manage database objects efficiently.

• Joins
• LEFT
• INNER
• FULL OUTER
• SELF
• Schema
• CREATE
• DROP
• ALTER

Roles & Permissions

Roles and permissions in PostgreSQL control user access and database security by managing privileges and role-based operations.

• CREATE ROLE
• ALTER ROLE
• DROP ROLE
• GRANT
• REVOKE
• Role Membership

In-Built Functions

PostgreSQL in-built functions simplify calculations, string manipulation, date handling and data processing operations within queries.

• AVG()
• COUNT()
• MAX()
• MIN()
• SUM()
• ROW NUMBER
• CURRENT DATE
• EXTRACT
• CONCAT
• FORMAT
• UPPER
• LOWER
• REPLACE

Indexes

Indexes in PostgreSQL improve query performance by allowing faster data retrieval and efficient searching on database tables.

• CREATE INDEX
• DROP INDEX
• UNIQUE Index
• Multicolumn Indexes

Advanced PostgreSQL

Advanced PostgreSQL concepts help you work with procedures, triggers, transactions, exception handling and other important database features.

• Variables
• Constants
• Block Structure
• Stored Procedures
• CTE
• Transactions
• Trigger
• Exception Handling

Exercises & Interview Questions

PostgreSQL exercises and interview questions help strengthen practical knowledge and prepare for real-world database development and job interviews.

• Exercises
• Interview Questions and Answers
• PostgreSQL Cheat Sheet

Related Articles

• SQL Tutorial
• Install PostgreSQL on Mac
• Install PostgreSQL on Linux