This post is a part of the DP-900: Microsoft Azure Data Fundamentals Exam Prep Hub. 
This topic falls under these sections:
Identify considerations for relational data on Azure (20–25%)
   --> Describe relational concepts
      --> Identify common Structured Query Language (SQL) statements

Note that there are 10 practice questions (with answers and explanations) for each section to help you solidify your knowledge of the material. Also, there are 2 practice tests with 60 questions each available on the hub below the exam topics section.

Understanding basic SQL statements is essential for working with relational data and is a key requirement for the DP-900 exam. You are not expected to be an advanced SQL developer, but you should recognize common SQL commands, their purpose, and when they are used.

What Is SQL?

Structured Query Language (SQL) is the standard language used to:

• Query data
• Insert new data
• Update existing data
• Delete data
• Define database structures

SQL is used across relational database systems, including Azure services like:

• Azure SQL Database
• Azure Database for PostgreSQL
• Azure Database for MySQL

Categories of SQL Statements

SQL statements are typically grouped into categories:

For DP-900, focus primarily on DDL, DML, and DQL.

1. Data Query Language (DQL)

SELECT

Used to retrieve data from a table.

SELECT Name, City
FROM Customers;

You can filter results:

SELECT Name
FROM Customers
WHERE City = 'Seattle';

💡 Key Points:

• Most commonly used SQL statement
• Can include filtering, sorting, and grouping

2. Data Manipulation Language (DML)

INSERT

Adds new rows to a table.

INSERT INTO Customers (Name, City)
VALUES ('John', 'Seattle');

UPDATE

Modifies existing data.

UPDATE Customers
SET City = 'Austin'
WHERE Name = 'John';

DELETE

Removes rows from a table.

DELETE FROM Customers
WHERE Name = 'John';

💡 Important:
Always use a WHERE clause with UPDATE and DELETE to avoid affecting all rows.

3. Data Definition Language (DDL)

CREATE

Creates new database objects such as tables.

CREATE TABLE Customers (
    CustomerID INT PRIMARY KEY,
    Name VARCHAR(100),
    City VARCHAR(50)
);

ALTER

Modifies an existing table.

ALTER TABLE Customers
ADD Email VARCHAR(100);

DROP

Deletes a table or database object.

DROP TABLE Customers;

💡 Warning:
DROP permanently removes the object and its data.

4. Additional Common SQL Clauses

WHERE

Filters rows:

SELECT * FROM Orders
WHERE Amount > 100;

ORDER BY

Sorts results:

SELECT * FROM Orders
ORDER BY Amount DESC;

GROUP BY

Aggregates data:

SELECT City, COUNT(*)
FROM Customers
GROUP BY City;

JOIN

Combines data from multiple tables:

SELECT Orders.OrderID, Customers.Name
FROM Orders
JOIN Customers
ON Orders.CustomerID = Customers.CustomerID;

💡 DP-900 Tip:
You don’t need deep JOIN knowledge — just understand that JOINs combine related tables.

SQL in Azure

SQL is used across many Azure services:

Azure SQL Database

• Fully managed relational database
• Uses T-SQL (Microsoft’s SQL variant)

Azure Synapse Analytics

• Used for analytical queries on large datasets

Azure Database for PostgreSQL

• Uses PostgreSQL SQL dialect

Why This Matters for DP-900

On the exam, you may be asked to:

• Identify what a SQL statement does
• Match commands to their purpose (SELECT, INSERT, etc.)
• Recognize DDL vs DML
• Understand basic query concepts like filtering and sorting

Summary — Exam-Relevant Takeaways

✔ SELECT → Retrieve data
✔ INSERT → Add new data
✔ UPDATE → Modify existing data
✔ DELETE → Remove data

✔ CREATE / ALTER / DROP → Define and modify structures
✔ WHERE → Filter results
✔ ORDER BY → Sort data
✔ GROUP BY → Aggregate data
✔ JOIN → Combine tables

✔ SQL is the standard language for relational databases

Go to the Practice Exam Questions for this topic.

Go to the Additional Practice Questions for this topic.

Go to the DP-900 Exam Prep Hub main page.