What is aggregate function in sql

Aggregation functions in SQL are functions that perform calculations on a set of rows and return a single value. They are used to summarize and aggregate data and extract meaningful insights, including COUNT(), SUM(), AVG() , MAX() and MIN(). They work by counting all rows, aggregating the results into a single value, and then returning the aggregated value, usually displayed in the row or column header.

#What are aggregate functions in SQL?

Aggregation functions in SQL are functions that perform calculations on a set of rows and return a single value. They are used to summarize and aggregate data to extract meaningful insights.

The role of aggregate functions

Aggregation functions operate on the data set in the following ways:

• Perform calculations on a given column across all rows .
• Aggregate calculation results into a single value.
• Returns the aggregated value, usually displayed in the row or column header.

Common aggregate functions

There are many built-in aggregate functions in SQL, including:

• COUNT() - calculation Number of rows
• SUM() - Calculate the sum of the values ​​in the given column
• AVG() - Calculate the average of the values ​​in the given column
• MAX() - Return Maximum value in the given column
• MIN() - Returns the minimum value in the given column

Aggregation using the aggregate function

Functions are often used with the GROUP BY clause to group specific columns and then perform aggregate calculations on each group.

For example, to calculate the total sales for each product category, you can use the following query:

<code class="sql">SELECT product_category, SUM(sales)
FROM sales_data
GROUP BY product_category;</code>

Advantages

Using aggregate functions has several Benefits:

• Aggregating data to gain meaningful insights
• Identifying trends and patterns in data
• Simplifying the writing of complex queries

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