Productivity

Productivity

Nov 22, 2025

Nov 22, 2025

SQL (Structured Query Language)

Learn SQL (Structured Query Language) basics for managing relational databases. Master queries, data manipulation, and analytics. Updated November 2025.

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Xavier Pladevall

Co-founder & CEO

image of Xavier Pladevall

Xavier Pladevall

SQL (Structured Query Language): Standard Language for Managing Relational Databases

What is SQL?

SQL (Structured Query Language) is the standard programming language used to manage and manipulate data in relational databases. In a relational database, data is organized into tables (rows and columns), and SQL provides a way to query and modify that tabular data. Using SQL, you can insert new data, update or delete existing data, and retrieve specific information from one or multiple tables with queries. In essence, SQL allows users to “ask questions” of the database and get back results, making it indispensable for data analysis and application development. SQL has been around since the 1970s (it was originally called SEQUEL) and remains extremely popular today as the primary language for database management. One reason for SQL’s enduring importance is that it is relatively easy to learn – its syntax uses many English-like keywords (such as SELECT, FROM, WHERE, etc.), which makes it approachable even for those without a programming background. At the same time, SQL is very powerful: it can handle complex queries that join multiple tables, aggregate data (e.g. computing sums or averages), and filter results based on conditions, all with concise statements.

Common Uses of SQL:

SQL is foundational in the world of databases and analytics. Some of the key uses and commands include:

  • Querying Data: The most famous SQL command is SELECT, which retrieves data from the database. Using SELECT with various clauses (JOIN, WHERE filters, ORDER BY sorting, etc.) allows users to pull exactly the data they need for analysis. For example, one can select all customers from a certain city or calculate the total sales per region with a single query.

  • Updating and Managing Data: SQL includes commands for data manipulation – e.g. INSERT (to add new records), UPDATE (to modify existing records), and DELETE (to remove records). This is often referred to as DML (Data Manipulation Language). There are also DDL (Data Definition Language) commands like CREATE TABLE or ALTER TABLE to define or change the database schema.

  • Database Administration: Beyond querying, SQL is used for defining user permissions, creating views, indexing for performance, and other administrative tasks (sometimes via extensions or specific SQL dialect features).

  • Analytics and Reporting: Data analysts and BI tools use SQL to aggregate data across millions of records. SQL’s aggregation functions and grouping (GROUP BY) enable summarizing large datasets — for example, an analyst might write an SQL query to get monthly user signup counts, or average daily active users, from raw event logs. Tools like Index often allow analysts to write custom SQL or automatically generate SQL (even via AI) to create charts and dashboards from database data.

Advantages for Data Analysis:

SQL has become the “meat and potatoes” of data analysis. Unlike spreadsheet tools, SQL queries are easy to document, share, and replicate for auditing – you can version-control a query or modify it and re-run it on updated data, ensuring consistent results. Queries can also handle large volumes of data far beyond what spreadsheet software can, since databases are optimized for such operations. For these reasons, many data analysts, product managers, and engineers rely on SQL to extract insights from databases on a daily basis. In summary, SQL is a foundational technology for databases. Whether you are building a product that requires storing user data, or performing analytics on millions of records, SQL is the tool that enables you to communicate with the relational database. Modern analytics platforms (like Index) leverage SQL under the hood – sometimes even auto-generating SQL queries – because it is a proven, powerful way to get answers from data. Anyone working with data will benefit from understanding SQL, as it remains the essential language for database querying and management.