Aggregates (count, sum, avg) in Laravel - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the output of this Laravel Eloquent aggregate query?

Consider a Laravel model Order with a total_price column. What does this code return?

Order::sum('total_price');

Laravel

use App\Models\Order;

$total = Order::sum('total_price');
echo $total;

A The count of all orders in the database

B The sum of all values in the total_price column across all orders

C The average value of total_price for all orders

D The maximum value of total_price among all orders

💡 Hint

Think about what the sum() method does in Laravel Eloquent.

The sum() method adds up all values in the specified column and returns the total sum.

📝 Syntax

intermediate

Which option correctly counts the number of users with active status in Laravel?

You want to count users where the status column equals 'active'. Which code snippet is correct?

Laravel

use App\Models\User;

$count = ???;
echo $count;

A User::where('status', 'active')->count();

B User::count()->where('status', 'active');

C User::where('status', 'active')->sum();

D User::sum('status', 'active');

💡 Hint

Remember that count() is called after filtering with where().

The where() method filters the query, then count() returns the number of matching records.

🔧 Debug

advanced

Why does this Laravel query cause an error?

Examine the code below:

$average = Product::avg();

What error will this produce and why?

Laravel

use App\Models\Product;

$average = Product::avg();

A Returns average of all columns automatically

B Returns 0 because no column specified

C Error: Missing argument 1 for avg(), column name is required

D SyntaxError due to missing parentheses

💡 Hint

Check the method signature for avg() in Laravel Eloquent.

The avg() method requires the column name as an argument to calculate the average.

❓ state_output

advanced

What is the value of $count after running this Laravel code?

Given the following code:

$count = User::where('age', '>', 30)->count();

Assuming the database has 5 users older than 30, what is the value of $count?

Laravel

use App\Models\User;

$count = User::where('age', '>', 30)->count();

A 5

B 0

C Number of all users regardless of age

D Throws an exception

💡 Hint

The where() filters users older than 30 before counting.

The count() method returns the number of records matching the where condition.

🧠 Conceptual

expert

Which Laravel aggregate method returns a float value representing the average of a column?

Select the method that returns the average value of a numeric column as a float in Laravel Eloquent.

A max()

B sum()

C count()

D avg()

💡 Hint

Think about which aggregate calculates the mean value.

The avg() method calculates the average (mean) of the specified column and returns a float.