Query patterns, joins, transactions, functions, and maintenance commands support Microsoft SQL Server workloads. Follow the SQL Server roadmap when you want depth beyond what fits on a single cheatsheet grid.

SQL Server learning roadmap — T-SQL, indexing, and administration topics sequenced like this reference.

SQL Server Cheatsheet

Quick reference guide for SQL Server database operations

Introduction to SQL

SQL (Structured Query Language) is the standard language for managing relational databases.

SQL Command Types
  • DDL: Data Definition Language (CREATE, ALTER, DROP)
  • DML: Data Manipulation Language (INSERT, UPDATE, DELETE)
  • DQL: Data Query Language (SELECT)
  • DCL: Data Control Language (GRANT, REVOKE)
  • TCL: Transaction Control Language (COMMIT, ROLLBACK)
Basic Example
SELECT TOP 10 * FROM customers 
WHERE country = 'USA' 
ORDER BY last_name;

Setting Up SQL Server Environment

Installation
  • SQL Server Express Edition
  • SQL Server Management Studio (SSMS)
  • Azure Data Studio
Online Tools
  • Azure SQL Database
  • SQL Fiddle (SQL Server mode)
  • DB Fiddle (SQL Server mode)
IDEs
  • SQL Server Management Studio
  • Azure Data Studio
  • Visual Studio with SQL Server Data Tools
  • DBeaver

Schema and Table Operations

User/Schema Creation
CREATE LOGIN my_user WITH PASSWORD = 'password';
CREATE USER my_user FOR LOGIN my_user;
ALTER USER my_user WITH DEFAULT_SCHEMA = dbo;
GRANT SELECT, INSERT, UPDATE, DELETE TO my_user;
Table Creation
CREATE TABLE employees (
  id INT PRIMARY KEY IDENTITY,
  name VARCHAR(100) NOT NULL,
  email VARCHAR(100) UNIQUE,
  hire_date DATE DEFAULT GETDATE(),
  salary DECIMAL(10,2) CHECK (salary > 0)
);

CREATE SEQUENCE emp_seq START WITH 1;
Common Data Types
  • INT, BIGINT: Integer values
  • VARCHAR(n): Variable string
  • DATE, DATETIME: Date and time
  • DATETIME2: Precise date/time
  • CHAR(n): Fixed-length string
  • DECIMAL(p,s): Exact numeric

Basic SQL Queries

Filtering Data
SELECT TOP 5 product_name, price
FROM products
WHERE price > 100 
  AND category = 'Electronics'
ORDER BY price DESC;
Sorting & Limiting
SELECT * FROM customers
ORDER BY last_name ASC, 
         first_name ASC
OFFSET 20 ROWS FETCH NEXT 10 ROWS ONLY;

Modifying Data (DML)

INSERT
INSERT INTO employees 
(name, email, salary)
VALUES 
('John Doe', 'john@example.com', 50000);
UPDATE
UPDATE employees
SET salary = salary * 1.1
WHERE department = 'Sales';
DELETE
DELETE FROM products
WHERE discontinued = 1;

Advanced Filtering

IN, BETWEEN, LIKE
SELECT * FROM products
WHERE category IN ('Electronics', 'Books')
  AND price BETWEEN 50 AND 200
  AND product_name LIKE '%Phone%';
NULL Handling
SELECT * FROM customers
WHERE phone IS NOT NULL;

UPDATE employees
SET manager_id = NULL
WHERE manager_id = 10;

Working with Multiple Tables

INNER JOIN
SELECT o.order_id, c.customer_name
FROM orders o
INNER JOIN customers c 
  ON o.customer_id = c.customer_id;
LEFT JOIN
SELECT e.name, d.department_name
FROM employees e
LEFT JOIN departments d
  ON e.dept_id = d.dept_id;
Self Join Example
SELECT e1.name AS employee, 
       e2.name AS manager
FROM employees e1
LEFT JOIN employees e2
  ON e1.manager_id = e2.employee_id;

Aggregation and Grouping

Aggregate Functions
SELECT 
  COUNT(*) AS total_products,
  AVG(price) AS avg_price,
  MIN(price) AS min_price,
  MAX(price) AS max_price,
  SUM(stock) AS total_stock
FROM products;
GROUP BY & HAVING
SELECT department_id, 
  COUNT(*) AS emp_count,
  AVG(salary) AS avg_salary
FROM employees
GROUP BY department_id
HAVING COUNT(*) > 5
ORDER BY avg_salary DESC;
Key Differences
  • WHERE filters before grouping
  • HAVING filters after grouping
  • Non-aggregated columns in SELECT must be in GROUP BY
  • Aggregate functions can't be used in WHERE

Subqueries

Single-Row Subquery
SELECT name, salary
FROM employees
WHERE salary > (
  SELECT AVG(salary)
  FROM employees
);
Multi-Row Subquery
SELECT product_name, price
FROM products
WHERE category_id IN (
  SELECT category_id
  FROM categories
  WHERE department = 'Electronics'
);
Correlated Subquery
SELECT e.name, e.salary, e.department_id
FROM employees e
WHERE salary > (
  SELECT AVG(salary)
  FROM employees
  WHERE department_id = e.department_id
);

Views and Indexes

Creating Views
CREATE OR ALTER VIEW high_paid_employees AS
SELECT id, name, salary, department
FROM employees
WHERE salary > 100000
WITH CHECK OPTION;

SELECT * FROM high_paid_employees;
Creating Indexes
CREATE INDEX idx_employee_name 
ON employees(name);

CREATE UNIQUE INDEX idx_customer_email
ON customers(email);

CREATE INDEX idx_order_dates
ON orders(order_date, shipped_date);
Index Best Practices
  • Index columns frequently used in WHERE, JOIN, ORDER BY
  • Avoid over-indexing (slows down INSERT/UPDATE)
  • Consider composite indexes for multi-column queries
  • Monitor index usage and remove unused indexes

Basic SQL Functions

String Functions
SELECT 
  first_name + ' ' + last_name AS full_name,
  UPPER(email) AS email_upper,
  SUBSTRING(phone, 1, 3) AS area_code,
  LEN(address) AS addr_length
FROM customers;
Date Functions
SELECT 
  GETDATE() AS current_datetime,
  CAST(order_date AS DATE) AS order_date_only,
  DATEDIFF(DAY, GETDATE(), due_date) AS days_remaining,
  DATEADD(MONTH, 12, hire_date) AS anniversary
FROM orders;
Math Functions
SELECT 
  ROUND(price * 1.1, 2) AS price_with_tax,
  ABS(discount) AS absolute_discount,
  quantity % 10 AS remainder,
  CEILING(weight) AS rounded_weight
FROM products;

Transactions and ACID

Transaction Control
BEGIN TRANSACTION;

UPDATE accounts 
SET balance = balance - 100
WHERE id = 123;

UPDATE accounts 
SET balance = balance + 100
WHERE id = 456;

COMMIT TRANSACTION;
-- or ROLLBACK TRANSACTION if error occurs
ACID Properties
  • Atomicity: All or nothing execution
  • Consistency: Valid state transitions
  • Isolation: Concurrent transactions don't interfere
  • Durability: Committed changes persist

Stored Procedures & Functions

Stored Procedure
CREATE OR ALTER PROCEDURE update_salary
  @emp_id INT,
  @increase_percent DECIMAL(5,2)
AS
BEGIN
  UPDATE employees
  SET salary = salary * (1 + @increase_percent/100)
  WHERE id = @emp_id;
  
  RETURN @@ROWCOUNT;
END;
GO

EXEC update_salary @emp_id = 101, @increase_percent = 10;
Scalar Function
CREATE OR ALTER FUNCTION get_employee_age(
  @emp_id INT
) RETURNS INT
AS
BEGIN
  DECLARE @age INT;
  
  SELECT @age = DATEDIFF(YEAR, birth_date, GETDATE())
  FROM employees
  WHERE id = @emp_id;
  
  RETURN @age;
END;
GO

SELECT name, dbo.get_employee_age(id) AS age
FROM employees;

Want to Practice SQL Server?

Try these concepts with real-world exercises

Start Practicing Now
Quick reference guide

Comprehensive SQL Server Query Cheatsheet Reference

This SQL Server Query cheatsheet on Nikhil Learn Hub collects syntax, commands, and practical snippets for quick revision. Practice SQL Server queries, joins, functions, stored procedures, and database operations with practical examples.

Use the reference cards and examples above during coding sessions; return here instead of scattered searches when you need dependable reminders. Follow the SQL Server learning roadmap when you want structured lessons beyond one-page lookups.

Quick lookup coverage

  • Syntax, commands, and API signatures
  • Copy-ready examples and common patterns
  • Terminology for coursework and interviews
  • Cross-links to the matching learning roadmap

How to study with this sheet

  • Production debugging and tuning reminders
  • Security, performance, or scale cautions
  • Integration with adjacent stacks on this site
  • Deeper study through tutorials and roadmaps

Who Should Use This Cheatsheet

Students, self-taught developers, and professionals who need fast SQL Server Query lookups during labs, debugging, or interview revision should keep this page bookmarked.

Related Resources on Nikhil Learn Hub