MIN and MAX functions in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the highest salary from the employees table.

SQL

SELECT [1](salary) FROM employees;

Drag options to blanks, or click blank then click option'

AMIN

BMAX

CCOUNT

DSUM

Attempts:

3 left

💡 Hint

Common Mistakes

Using MIN instead of MAX.

Using SUM or COUNT which do different calculations.

The MAX function returns the highest value in a column. Here, it finds the highest salary.

2fill in blank

medium

Complete the code to find the lowest price in the products table.

SQL

SELECT [1](price) FROM products;

Drag options to blanks, or click blank then click option'

AAVG

BSUM

CMAX

DMIN

Attempts:

3 left

💡 Hint

Common Mistakes

Using MAX instead of MIN.

Using AVG or SUM which calculate averages or totals.

The MIN function returns the smallest value in a column. Here, it finds the lowest price.

3fill in blank

hard

Fix the error in the code to get the maximum age from the users table.

SQL

SELECT [1](age) FROM users;

Drag options to blanks, or click blank then click option'

AMAX

BMIN

CMAX)

DMAX(

Attempts:

3 left

💡 Hint

Common Mistakes

Leaving unbalanced parentheses.

Using MIN instead of MAX.

The function name should be MAX and the parentheses must be balanced. The blank replaces the function name correctly.

4fill in blank

hard

Fill both blanks to find the minimum and maximum scores from the tests table.

SQL

SELECT [1](score) AS min_score, [2](score) AS max_score FROM tests;

Drag options to blanks, or click blank then click option'

AMIN

BSUM

CMAX

DCOUNT

Attempts:

3 left

💡 Hint

Common Mistakes

Using SUM or COUNT instead of MIN or MAX.

Swapping MIN and MAX functions.

MIN finds the smallest score and MAX finds the largest score in the tests table.

5fill in blank

hard

Fill all three blanks to select the maximum price, minimum price, and average price from the items table.

SQL

SELECT [1](price) AS max_price, [2](price) AS min_price, [3](price) AS avg_price FROM items;

Drag options to blanks, or click blank then click option'

AMAX

BMIN

CAVG

DSUM

Attempts:

3 left

💡 Hint

Common Mistakes

Using SUM instead of AVG for average price.

Mixing up MIN and MAX functions.

MAX finds the highest price, MIN finds the lowest price, and AVG calculates the average price.

Practice

1. What does the SQL function MIN() do when applied to a column of numbers?

easy

A. Calculates the average of the numbers

B. Finds the largest number in the column

C. Finds the smallest number in the column

D. Counts the total numbers in the column

Solution

1. Step 1: Understand the purpose of MIN()

   The MIN() function is designed to find the smallest value in a column of data.

2. Step 2: Compare with other functions

   Unlike MAX() which finds the largest, or AVG() which calculates average, MIN() specifically returns the minimum value.

3. Final Answer:

   Finds the smallest number in the column -> Option C

4. Quick Check:

   MIN() = smallest value [OK]

Hint: MIN() always returns the smallest value in a column [OK]

Common Mistakes:

• Confusing MIN() with MAX()
• Thinking MIN() calculates average
• Using MIN() to count rows

2. Which of the following is the correct syntax to find the maximum salary from a table named Employees?

easy

A. SELECT MAX salary FROM Employees;

B. SELECT MAX{salary} FROM Employees;

C. SELECT MAX[salary] FROM Employees;

D. SELECT MAX(salary) FROM Employees;

Solution

1. Step 1: Recall correct function syntax

   The correct syntax for SQL aggregate functions like MAX() requires parentheses around the column name.

2. Step 2: Check syntax

   SELECT MAX(salary) FROM Employees; uses MAX(salary) which is correct. Forms without parentheses or using [] {} are invalid.

3. Final Answer:

   SELECT MAX(salary) FROM Employees; -> Option D

4. Quick Check:

   MAX() uses parentheses around column [OK]

Hint: Use parentheses around column name in MAX() [OK]

Common Mistakes:

• Omitting parentheses in function calls
• Using square or curly brackets instead of parentheses
• Misspelling function names

3. Given the table Products with a column Price containing values (100, 250, 50, 400), what will the query SELECT MIN(Price), MAX(Price) FROM Products; return?

medium

A. (400, 50)

B. (50, 400)

C. (100, 250)

D. (0, 400)

Solution

1. Step 1: Identify minimum price

   From the values (100, 250, 50, 400), the smallest price is 50.

2. Step 2: Identify maximum price

   The largest price in the list is 400.

3. Final Answer:

   (50, 400) -> Option B

4. Quick Check:

   MIN = 50, MAX = 400 [OK]

Hint: MIN returns smallest, MAX returns largest value [OK]

Common Mistakes:

• Mixing up MIN and MAX values
• Assuming default zero minimum
• Confusing order of returned values

4. What is wrong with this query to find the maximum age from the Users table?
SELECT MAX age FROM Users;

medium

A. Missing parentheses around the column name

B. MAX function cannot be used on numeric columns

C. Table name should be in quotes

D. MAX should be lowercase

Solution

1. Step 1: Check function syntax

   The MAX() function requires parentheses around the column name, so MAX age is invalid syntax.

2. Step 2: Verify other options

   MAX works on numeric columns, table names don't need quotes, and function names are case-insensitive in SQL.

3. Final Answer:

   Missing parentheses around the column name -> Option A

4. Quick Check:

   MAX() needs parentheses [OK]

Hint: Always use parentheses with MAX() [OK]

Common Mistakes:

• Omitting parentheses in function calls
• Thinking MAX() only works on strings
• Adding unnecessary quotes around table names

5. You have a table Orders with columns OrderID, CustomerID, and TotalAmount. How would you write a query to find the highest order amount for each customer?

hard

A. SELECT CustomerID, MAX(TotalAmount) FROM Orders GROUP BY CustomerID;

B. SELECT MAX(TotalAmount) FROM Orders WHERE CustomerID;

C. SELECT CustomerID, MAX(TotalAmount) FROM Orders;

D. SELECT CustomerID, TotalAmount FROM Orders WHERE MAX(TotalAmount);

Solution

1. Step 1: Understand grouping requirement

   To find the highest order amount per customer, we must group data by CustomerID.

2. Step 2: Use MAX() with GROUP BY

   Using MAX(TotalAmount) with GROUP BY CustomerID returns the maximum order amount for each customer.

3. Step 3: Why others fail

   Using MAX() in a WHERE clause is invalid, WHERE CustomerID; is meaningless, and selecting CustomerID with MAX() without GROUP BY causes an error because CustomerID is not aggregated.

4. Final Answer:

   SELECT CustomerID, MAX(TotalAmount) FROM Orders GROUP BY CustomerID; -> Option A

5. Quick Check:

   Use GROUP BY with MAX() for per-group max [OK]

Hint: Use GROUP BY with MAX() to get max per group [OK]

Common Mistakes:

• Forgetting GROUP BY when using MAX per group
• Using MAX() in WHERE clause incorrectly
• Selecting columns without grouping