What is PostgreSQL? How is it different from SQL?

What is PostgreSQL? How is it different from SQL?

Welcome to this blog post on codedamn. If you’ve ever dabbled in the realm of databases, you’ve probably come across the terms SQL and PostgreSQL. While they both revolve around databases, they serve different roles. In this article, you will learn what SQL is, its historical background, key features, standardization, and implementations. Then, we’ll move on to PostgreSQL, its origins, unique features, and how it differs from SQL.

What is SQL?

SQL, or Structured Query Language, is a domain-specific language designed for managing and manipulating relational databases.

Historical Background

SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce in the early 1970s. The main purpose of SQL was to provide an efficient way to access and manipulate data stored in IBM’s original quasi-relational database management system, System R. Over the years, SQL has evolved to become the standard language for relational database management systems.

Key Features

SQL is primarily known for its CRUD operations — Create, Read, Update, and Delete. But it is much more than just these operations. It supports a wide variety of functions like sorting (ORDER BY), filtering (WHERE), and aggregating (GROUP BY) data. SQL also has powerful joining capabilities to combine records from two or more tables.


The American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) have released standards for SQL. The ANSI SQL standard was first published in 1986 and since then, it has been revised to include new functionalities like XML integration, regular expression matching, and JSON querying.


Various databases implement SQL, each with their own additional features and slight syntax variations. Some well-known databases that use SQL are MySQL, SQLite, and MS SQL Server.

What is PostgreSQL?

PostgreSQL is an open-source relational database management system (RDBMS) that uses and extends the SQL language.

Historical Background

PostgreSQL was initially developed at the University of California, Berkeley, in 1996. It originated as a follow-on project to the earlier Ingres database, which was also developed at Berkeley. Currently, it is maintained by the PostgreSQL Global Development Group, a coalition of many companies and individual contributors.

Key Features

Among its many features, PostgreSQL is lauded for its ACID (Atomicity, Consistency, Isolation, Durability) properties that guarantee that all database transactions are processed reliably. Furthermore, PostgreSQL is extensible, allowing users to define their own data types, operators, and even write custom code to process data. It supports a variety of built-in data types like JSON, XML, and arrays, which makes it incredibly flexible.

For an in-depth look into PostgreSQL features, you can refer to their official documentation.


PostgreSQL operates on a client-server model where the server manages the database and the client interacts with the server to perform operations. Multiple clients can connect to the server simultaneously, making it well-suited for multi-user environments.

One of PostgreSQL’s unique features is its support for Multi-Version Concurrency Control (MVCC). MVCC allows for multiple versions of a data record to exist at the same time, improving read-write concurrency and overall system performance. This ensures that reads are never blocked by writes and vice versa, resulting in higher throughput and reduced contention.

Popular Use Cases

PostgreSQL is frequently used for web application backends, data warehousing, and Geospatial databases, thanks to its support for complex queries and transactions. Its extensibility makes it ideal for specialized applications like JSON data stores or time-series databases. Startups to large enterprises alike prefer it for its robustness and capabilities.

SQL vs. PostgreSQL: Points of Differentiation

To understand the differences between SQL and PostgreSQL, let’s delve into the characteristics that distinguish them.

Language vs. Database

SQL (Structured Query Language) is a standardized language for querying and manipulating databases. PostgreSQL, on the other hand, is a Database Management System (DBMS) that uses SQL as its query language. Simply put, SQL is the language, and PostgreSQL is the software that utilizes that language.

Standard SQL Support

PostgreSQL is known for its strict adherence to SQL standards, but it also provides several extensions. This includes support for advanced data types like JSON and hstore (key-value store), indexing techniques like GiST (Generalized Search Tree), and various other features that make it more powerful than standard SQL.


When it comes to speed and optimization, PostgreSQL offers several performance-enhancing features like advanced indexing techniques, partitioning, and query optimization based on cost-based algorithms. However, it’s worth noting that performance can be highly situational and dependent on the specific use case and system architecture.


PostgreSQL can scale vertically by adding more powerful hardware resources. Horizontal scalability, although possible, typically involves using additional software solutions and can be more complex to implement.


One of the hallmarks of PostgreSQL is its extensibility. You can create custom data types, operators, and even write your own procedural languages for the system. This allows for highly customized solutions tailored to specific business needs.

Ecosystem and Community

PostgreSQL enjoys robust community support, with a plethora of third-party tools, libraries, and extensions. This leads to faster issue resolution and the rapid development of new features.

Use Cases: When to Use What?

Choose PostgreSQL for complex queries, ACID-compliant transactions, and when you need high extensibility. For simpler, read-heavy workloads, a NoSQL database or lighter SQL databases like SQLite may be more appropriate.

Examples and Code Snippets

Let’s take a practical approach by diving into some examples and code snippets to highlight PostgreSQL’s features.

Basic SQL Queries in PostgreSQL

Here’s a simple SELECT query:

SELECT * FROM employees WHERE department = 'Engineering';

Unique Features in PostgreSQL

One unique feature is the support for JSON data types:

SELECT * FROM table WHERE data->>'key' = 'value';

Common Misconceptions

A common misconception is that PostgreSQL is slow and not suitable for large datasets. In fact, with proper tuning and hardware, it can handle petabytes of data.


Whether you’re a startup or an established enterprise, PostgreSQL offers robust, scalable, and extensible database solutions. Its strong community support and rich feature set make it an excellent choice for a wide range of applications.

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