Aggregate functions in SQL Server

Question

What are aggregate functions in SQL Server and its Types

Harshit Pandey · Answer

In SQL Server, aggregate functions are built-in functions that perform a calculation on a set of values and return a single summarized result. They are commonly used with the GROUP BY clause to group rows that share the same values into summary rows. Common Types of Aggregate Functions: SUM() Calculates the total sum of a numeric column. Example: SELECT SUM(Salary) FROM Employees; AVG() Returns the average value of a numeric column. Example: SELECT AVG(Age) FROM Users; COUNT() Returns the number of rows that match a specified condition. Example: SELECT COUNT(*) FROM Orders; MIN() Returns the smallest value in a column. Example: SELECT MIN(Price) FROM Products; MAX() Returns the largest value in a column. Example: SELECT MAX(Score) FROM Results; COUNT(DISTINCT column) Returns the number of unique (non-duplicate) values. Example: SELECT COUNT(DISTINCT Department) FROM Employees; Note: Aggregate functions ignore NULL values (except COUNT(*) , which counts all rows).

Cynthia Sathuragiri · Answer

Aggregate functions are used to calculate a single value from a group of values in a table, like total, average, minimum, or maximum. COUNT() – Counts how many rows or values are there. SUM() – Adds up all the numbers in a column. AVG() – Finds the average of numbers. MIN() – Finds the smallest value. MAX() – Finds the largest value.

Sandhiya Priya · Answer

Aggregate functions in SQL Server are used to perform calculations on multiple values and return a single summary value . They are commonly used with GROUP BY for reporting and analysis. Here are the most commonly used aggregate functions: 1. SUM() Returns the total sum of a numeric column. SELECT SUM(Salary) AS TotalSalary FROM Employees; 2. AVG() Returns the average value. SELECT AVG(Salary) AS AverageSalary FROM Employees; 3. COUNT() Returns the number of rows. SELECT COUNT(*) AS TotalEmployees FROM Employees; 4. MAX() Returns the maximum value. SELECT MAX(Salary) AS HighestSalary FROM Employees; 5. MIN() Returns the minimum value. SELECT MIN(Salary) AS LowestSalary FROM Employees; Example with GROUP BY: SELECT Department, AVG(Salary) AS AvgSalary FROM Employees GROUP BY Department; This shows the average salary per department.

Aggregate functions in SQL Server

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