SQL is based on formal standards that define common ways of interacting with relational databases. ANSI and ISO have been involved in defining SQL standards. Database systems such as Microsoft SQL Server, MySQL, PostgreSQL, Oracle, and SQLite support many common SQL concepts, but they can also provide their own functions, syntax, and extensions. Therefore, SQL is standardized but not every SQL feature is identical across every database platform.
Understanding SQL standards helps you recognize the difference between generally portable SQL and database-specific SQL. This becomes important when moving from one database platform to another or when preparing for SQL interviews involving different technologies.
SELECT, WHERE, GROUP BY, ORDER BY, JOIN, COUNT, SUM, and AVG are common SQL concepts supported by many database systems. However, features such as limiting rows or working with dates can use different syntax depending on the database platform.
SELECT
EmployeeName,
Department
FROM Employees
WHERE Department = 'Finance';A Data Analyst may work with SQL Server in one company and PostgreSQL or MySQL in another. Understanding standard SQL makes it easier to adapt to a new database system.
- SQL has formal standards.
- ANSI and ISO are associated with SQL standards.
- Different database systems support common SQL concepts.
- Database systems can provide additional features.
- Some SQL syntax differs between platforms.
- Learning standard SQL provides a strong foundation.
Is SQL exactly the same in every database system?
No. Database systems support common SQL standards but can have different syntax, functions, and platform-specific features.
Why are SQL standards important?
SQL standards provide common rules and syntax that help SQL concepts remain consistent across different relational database systems.