Introduction to Group By Vs Distinct Clause

GROUP BY and DISTINCT Clauses both are used to get the unique value from a column or a set of columns. But they are different in the way they are used.

• The functionality of DISTINCT: It Removes the Duplicates.
• Functionality of GROUP BY (Functionality of DISTINCT The functionality) + Applying Aggregate Function on that group.

Let’s Create a table to understand both the clause. We will be creating a table of Employees.

Query to Create a table

CREATE TABLE Employee 
(
    EmployeeID INT PRIMARY KEY,
    FirstName VARCHAR(50),
    LastName VARCHAR(50),
    Department VARCHAR(50),
    Salary DECIMAL(10, 2)
);

Query to Insert data into it

INSERT INTO Employee (EmployeeID, FirstName, LastName, Department, Salary)
VALUES
    (1, 'John', 'Doe', 'IT', 60000.00),
    (2, 'Jane', 'Smith', 'HR', 55000.00),
    (3, 'Bob', 'Johnson', 'IT', 65000.00),
    (4, 'Alice', 'Williams', 'Finance', 70000.00),
    (5, 'Charlie', 'Brown', 'HR', 60000.00),
    (6, 'David', 'Miller', 'Finance', 75000.00),
    (7, 'Eva', 'Davis', 'IT', 62000.00),
    (8, 'Frank', 'Clark', 'Finance', 72000.00),
    (9, 'Grace', 'Moore', 'HR', 58000.00),
    (10, 'Harry', 'Young', 'IT', 63000.00),
    (11, 'Isabel', 'Hall', 'HR', 59000.00),
    (12, 'Jack', 'Baker', 'Finance', 71000.00),
    (13, 'Olivia', 'Turner', 'IT', 60000.00),
    (14, 'Paul', 'Moore', 'Finance', 73000.00),
    (15, 'Quinn', 'Parker', 'HR', 60000.00),
    (16, 'Ryan', 'Scott', 'IT', 64000.00),
    (17, 'Samantha', 'Bryant', 'HR', 61000.00),
    (18, 'Tyler', 'Ward', 'Finance', 70000.00),
    (19, 'Ursula', 'Hill', 'IT', 61000.00),
    (20, 'Victor', 'Gomez', 'HR', 59000.00),
    (21, 'Wendy', 'Fisher', 'IT', 62000.00),
    (22, 'Xavier', 'Jordan', 'Finance', 71000.00),
    (23, 'Yvonne', 'Lopez', 'HR', 58000.00),
    (24, 'Zachary', 'Evans', 'IT', 63000.00),
    (25, 'Ava', 'Hernandez', 'Finance', 69000.00);

Our Table Looks Like:

Distinct is a relational database management system. SQL Server offers a wide range of features and tools that handle different needs, from small-scale applications to large-scale application solutions. GROUP BY has performance features, especially when dealing with large datasets and complex aggregations. DISTINCT is generally more effective and more efficient when the purpose is to obtain unique values.

In this article, we will understand the Group By vs. Distinct Difference In SQL Server with examples and so on.