Why is denormalization used in SQL databases and what are its advantages?

Denormalization in SQL databases is used to improve read performance by storing redundant data.

Advantages of denormalization:

• Reduces the number of JOIN queries, speeding up data retrieval.
• Increases application response speed when reading data.
• Simplifies queries and logic on the application side.

However, denormalization increases data maintenance complexity, as redundant copies need to be synchronized during updates.

Example: instead of storing a user's address in a separate table, it can be duplicated in the orders table for quick access without JOIN.