Basic SQL Queries for Beginners in MS SQL Server

Microsoft SQL Server (MSSQL) is one of the most popular relational database management systems (RDBMS) used for storing and managing data. Whether you're a beginner or looking to refresh your SQL skills, learning basic queries is essential to interact with databases effectively.

In this guide, we'll cover fundamental SQL queries in MS SQL Server with practical examples.

What is SQL?

SQL (Structured Query Language) is a standard language used to interact with databases. In MS SQL Server, SQL is used to retrieve, insert, update, and delete data from tables.

Before we start, make sure you have Microsoft SQL Server installed, along with SQL Server Management Studio (SSMS) to execute these queries.

1. Retrieving Data (SELECT Statement)

The SELECT statement is used to fetch data from a table.

Example 1: Retrieve all columns from a table

SELECT * FROM Employees;

This query retrieves all records and columns from the Employees table.

Example 2: Retrieve specific columns

SELECT FirstName, LastName FROM Employees;

This query fetches only the FirstName and LastName columns.

2. Filtering Data (WHERE Clause)

The WHERE clause is used to filter records based on a condition.

Example: Retrieve employees from the 'IT' department

SELECT * FROM Employees WHERE Department = 'IT';

Example: Retrieve employees hired after January 1, 2023

SELECT * FROM Employees WHERE HireDate > '2023-01-01';

3. Sorting Data (ORDER BY Clause)

The ORDER BY clause is used to sort results in ascending (ASC) or descending (DESC) order.

Example: Sort employees by salary in descending order

SELECT * FROM Employees ORDER BY Salary DESC;

Example: Sort employees by department and then by salary in ascending order

SELECT * FROM Employees ORDER BY Department ASC, Salary ASC;

4. Limiting Results (TOP & OFFSET FETCH)

Unlike MySQL and PostgreSQL, MSSQL uses TOP instead of LIMIT.

Example: Retrieve the top 5 highest-paid employees

SELECT TOP 5 * FROM Employees ORDER BY Salary DESC;

For pagination, MSSQL uses OFFSET and FETCH.

Example: Skip the first 5 records and fetch the next 5

SELECT * FROM Employees ORDER BY Salary DESC OFFSET 5 ROWS FETCH NEXT 5 ROWS ONLY;

5. Aggregating Data (GROUP BY Clause)

Aggregation functions like COUNT(), SUM(), AVG(), and MAX() help summarize data.

Example: Count employees in each department

SELECT Department, COUNT(*) AS EmployeeCount FROM Employees GROUP BY Department;

Example: Find the average salary in each department

SELECT Department, AVG(Salary) AS AvgSalary FROM Employees GROUP BY Department;

6. Joining Tables (INNER JOIN, LEFT JOIN, RIGHT JOIN)

Joins allow you to retrieve data from multiple tables.

Example: Retrieve employee names with their department names

SELECT e.FirstName, e.LastName, d.DepartmentName  
FROM Employees e  
INNER JOIN Departments d ON e.DepartmentID = d.DepartmentID;

This query fetches employee details along with their department names.

7. Modifying Data (INSERT, UPDATE, DELETE)

You can modify data using INSERT, UPDATE, and DELETE statements.

Insert Data into a Table

INSERT INTO Employees (FirstName, LastName, Department, Salary)  
VALUES ('Shrinivas', 'Baddi', 'IT', 22000);

Update Data in a Table

UPDATE Employees  
SET Salary = 50000  
WHERE FirstName = 'Shrinivas' AND LastName = 'Baddi';

Delete Data from a Table

DELETE FROM Employees WHERE FirstName = 'Shrinivas' AND LastName = 'Baddi';

8. Using Built-in Functions

MSSQL provides various built-in functions for data manipulation.

Example: Get current date and time

SELECT GETDATE();

Example: Convert a date to a different format

SELECT FORMAT(GETDATE(), 'yyyy-MM-dd');

Example: Convert text to uppercase

SELECT UPPER('hello world');

Conclusion

These basic MS SQL Server queries will help you interact with databases efficiently. Whether you're retrieving data, filtering results, or modifying records, mastering these SQL queries is essential for working with Microsoft SQL Server.

If you're new to MSSQL, practice these queries in SQL Server Management Studio (SSMS) to build confidence.

Let us know in the comments if you found this guide helpful! 🚀

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