What are the advantages and disadvantages of using SQL relational databases?

Relational SQL databases have the following advantages:

• Strict data structure: tables with clearly defined schemas ensure data integrity.
• Powerful query language: SQL allows easy execution of complex selections, joins, and aggregations.
• Transactions: support for ACID transactions guarantees data reliability and consistency.
• Wide support and maturity: numerous tools, documentation, and communities.

Disadvantages:

• Scalability: more difficult to scale horizontally compared to NoSQL.
• Flexibility: changing the schema can be labor-intensive when requirements change.
• Performance: very large volumes of data or complex queries may require optimization.

Example of a simple SQL query:

SELECT name, age FROM users WHERE age > 18 ORDER BY age DESC;