What is nomalization? Difference between rank and dense rank? Find nth highest salary

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Accepted Answer

Normalization is the process of organizing data in a database to eliminate redundancy and improve data integrity.

Normalization helps in reducing data redundancy by breaking down a large table into smaller, more manageable tables.
It ensures that each piece of data is stored only once, reducing the chances of inconsistencies.
Normalization follows a set of rules called normal forms, such as First Normal Form (1NF), Second Normal Form (2NF), etc.
Rank and dense rank are used in SQL to assign a unique rank to each row in a result set based on a specified column.
The main difference is that dense rank leaves no gaps in the ranking sequence, while rank may have gaps.
For example, if we have a table of employees with their salaries, we can find the nth highest salary using the RANK() or DENSE_RANK() functions in SQL.

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