What Is PostgreSQL and What Is It Used For?

PostgreSQL is an open-source relational database management system (RDBMS) that stores data in tables and is queried with SQL. It belongs to the same family as SQLite, MySQL, Oracle, and Microsoft SQL Server — all of which support the common SQL language standard, though each differs in the extra features and storage types it offers. PostgreSQL is a practical choice when you need safe, scalable storage for a website, mobile application, or data analysis workload.

Where PostgreSQL fits among relational databases

A relational database is a collection of related two-dimensional tables. Each table has a fixed number of named columns (the attributes of the table) and any number of rows of data — conceptually similar to a spreadsheet. For example, a vehicle registry table might store the make/model, number of wheels, number of doors, and type for each vehicle:

PostgreSQL, MySQL, SQLite, Oracle, and SQL Server all read and write this kind of structure using the shared SQL standard. The differences show up in the additional features and storage types each system supports — which is why the same SQL skills transfer across all of them, while the choice of engine depends on your project's requirements.

What PostgreSQL is used for

Because SQL databases provide safe and scalable storage, they sit behind millions of websites and mobile applications. PostgreSQL fits that role wherever you need:

• Application backends — persistent storage for user accounts, content, orders, and other structured records.
• Websites and mobile apps — the same scalable storage pattern used across the industry.
• Data querying and transformation — SQL is designed so both technical and non-technical users can query, manipulate, and transform data.
• Analytical work — aggregating, filtering, sorting, and joining data across multiple tables.

Do you need to learn PostgreSQL specifically to start?

No. If your goal is to learn SQL itself, you can practice the common standard in a browser with interactive lessons and exercises — no PostgreSQL installation required. SQLBolt, for instance, teaches the shared SQL language through in-browser exercises covering:

• SELECT queries and queries with constraints
• Filtering and sorting results
• Multi-table queries with JOIN and OUTER JOIN
• Handling NULL values
• Queries with expressions and aggregates
• Query order of execution
• Inserting, updating, and deleting rows
• Creating, altering, and dropping tables
• Subqueries, unions, intersections, and exceptions

Because PostgreSQL supports this common standard, the syntax you learn in those lessons applies directly when you later move to PostgreSQL.

A sensible learning order

1. Learn general SQL first — SELECT, WHERE, JOIN, aggregates, and table modification. This is the portable core.
2. Practice interactively — use browser-based exercises so you get immediate feedback without setting up a server.
3. Then explore PostgreSQL-specific features — once the standard syntax is comfortable, look into the additional capabilities and storage types PostgreSQL supports beyond the common standard.

If you are choosing a database for a new project, PostgreSQL is one of the established open-source relational options alongside SQLite and MySQL. Pick it when you want a full relational system with room to grow; pick SQLite when you want something lightweight and embedded. Either way, the SQL you write will look largely the same.