SQL Analytical Functions

In SQL, analytical functions are functions that perform calculations on a set of rows and return a single result per row. They are often used to compute aggregates, such as sums and averages, or to perform ranking and partitioning operations.

There are several types of analytical functions available in SQL, including:

• Aggregate functions: Aggregate functions perform calculations on a set of values and return a single result. Common aggregate functions include SUM, AVG, MIN, and MAX.
• Ranking functions: Ranking functions assign a rank to each row within a result set based on a specific value or set of values. Common ranking functions include ROW_NUMBER, RANK, and DENSE_RANK.
• Partitioning functions: Partitioning functions divide a result set into groups based on a specific value or set of values. Common partitioning functions include NTILE and ROW_NUMBER.

Here is an example of using an aggregate function in a SELECT statement:

SELECT AVG(price)
FROM products;

This example calculates the average value of the "price" column in the "products" table. The result of the AVG function will be a single value representing the average price of all products in the table.

Here is an example of using a ranking function in a SELECT statement:

SELECT product_name, price, RANK() OVER (ORDER BY price DESC) as price_rank
FROM products;

This example calculates the rank of each product based on its price, with the highest price ranked first. The RANK function is used in conjunction with the OVER clause, which specifies how the ranking should be performed. In this case, the ranking is based on the "price" column in descending order.

Analytical functions are a powerful tool for performing complex calculations and analysis on your data. They can be used in a variety of scenarios to extract insights and trends from your database, and can help you make more informed decisions about your data.