Query Data with SQL in PostgreSQL
When you want to retrieve information from a database, you query the database. These SQL statements are commonly called queries.
SQL is a powerful and flexible tool for database administration, data management and preparation for analysis. Unlike general-purpose programming languages like JavaScript or Python, SQL is a special-purpose language: its sole purpose is to interact with data.
A database is a container that helps logically organize data. A physical example is the card catalog in a library: each card represents a book, organized by category and containing additional information on each item.
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What's inside
7 sections- 1 Table of Contents
- 2 Understand the relational model
- 3 SELECT your data
- 4 Limit your results
- 5 Present and aggregate results
- 6 General Summary
- 7 SQL Commands Quick Reference
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