What Is SQL?
By Karthick Selvam · Published
SQL (Structured Query Language) is the standard language for working with relational databases.
What it does
Query data (SELECT), modify it (INSERT, UPDATE, DELETE), define structures (CREATE, ALTER) and control access (GRANT).
Core concepts
Tables, rows and columns; filtering with WHERE; joins; grouping and aggregation; subqueries; window functions.
Dialects
Databases like PostgreSQL, MySQL, SQL Server, Oracle, Snowflake and BigQuery share core SQL but differ in functions and extensions.
Why it matters
SQL is used by analysts, engineers, testers and scientists, which makes it one of the most transferable technical skills.
Frequently asked questions
Is SQL hard to learn?
The basics can be learned quickly; mastery of performance and complex logic takes practice.
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