SQL statement categories (DDL, DML, DQL, DCL) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Identify the category of the SQL statement

Which category does the following SQL statement belong to?

CREATE TABLE Students (ID INT, Name VARCHAR(100));

A Data Definition Language (DDL)

B Data Manipulation Language (DML)

C Data Query Language (DQL)

D Data Control Language (DCL)

💡 Hint

Think about whether this statement changes the structure of the database or the data inside it.

CREATE TABLE is used to define or change the structure of database objects, so it belongs to DDL.

🧠 Conceptual

intermediate

Classify the SQL statement type

What category does this SQL statement belong to?

SELECT * FROM Employees WHERE Department = 'Sales';

A Data Control Language (DCL)

B Data Manipulation Language (DML)

C Data Query Language (DQL)

D Data Definition Language (DDL)

💡 Hint

This statement retrieves data without changing it.

SELECT statements are used to query data, so they belong to DQL.

❓ query_result

advanced

Determine the effect of a DML statement

What will be the result of this SQL statement?

INSERT INTO Products (ID, Name) VALUES (101, 'Pen');
SELECT COUNT(*) FROM Products;

Assuming the Products table initially has 5 rows.

A Error: Cannot insert duplicate ID

B 5

C 0

D 6

💡 Hint

INSERT adds a new row to the table.

The INSERT statement adds one row, so the count increases by one.

📝 Syntax

advanced

Identify the correct DCL statement syntax

Which of the following SQL statements correctly grants SELECT permission on the Customers table to user 'Alice'?

A GRANT SELECT ON Customers TO Alice;

B GRANT SELECT FROM Customers TO Alice;

C GRANT SELECT Customers TO Alice;

D GRANT SELECT ON Customers FOR Alice;

💡 Hint

The correct syntax uses ON before the table name.

The GRANT statement syntax is: GRANT permission ON object TO user;

🔧 Debug

expert

Find the error in this mixed SQL statement

What error will this SQL code produce?

UPDATE Orders SET Status = 'Shipped' WHERE OrderID = 123;
GRANT DELETE ON Orders TO Bob;

A Runtime error on UPDATE statement

B No error, both statements run successfully

C Syntax error on GRANT statement

D Permission error on UPDATE statement

💡 Hint

Both UPDATE and GRANT are valid statements in their categories.

UPDATE is a DML statement and GRANT is a DCL statement; both are syntactically correct and valid.