Where clauses in Laravel - Mini Project: Build & Apply

Filtering Products with Laravel Where Clauses

📖 Scenario: You are building a simple product listing page for an online store. You want to show only products that meet certain conditions, like being in stock or having a price below a certain amount.

🎯 Goal: Build a Laravel query using where clauses to filter products by stock availability and price.

📋 What You'll Learn

Create a products array with product details

Add a variable maxPrice to set the price limit

Use Laravel's where clauses to filter products by in_stock and price

Return the filtered products collection

💡 Why This Matters

🌍 Real World

Filtering data like products or users based on conditions is common in web apps to show relevant information.

💼 Career

Understanding Laravel's where clauses helps you build efficient database queries and data filtering in real projects.

1

Create the products array

Create a variable called products as a Laravel collection containing these exact products: ['name' => 'Laptop', 'price' => 1200, 'in_stock' => true], ['name' => 'Mouse', 'price' => 25, 'in_stock' => true], ['name' => 'Keyboard', 'price' => 75, 'in_stock' => false], and ['name' => 'Monitor', 'price' => 300, 'in_stock' => true].

Laravel

$products = collect([
    // Your code here
]);

Hint

Use collect([]) to create a Laravel collection with the given product arrays inside.

2

Set the maximum price filter

Create a variable called maxPrice and set it to 100 to filter products cheaper than this price.

Laravel

$products = collect([
    ['name' => 'Laptop', 'price' => 1200, 'in_stock' => true],
    ['name' => 'Mouse', 'price' => 25, 'in_stock' => true],
    ['name' => 'Keyboard', 'price' => 75, 'in_stock' => false],
    ['name' => 'Monitor', 'price' => 300, 'in_stock' => true],
]);

// Your code here

Hint

Just create a simple variable $maxPrice and assign the number 100.

3

Filter products using where clauses

Use Laravel collection where clauses on $products to filter only products where in_stock is true and price is less than $maxPrice. Save the result in a variable called filteredProducts.

Laravel

$products = collect([
    ['name' => 'Laptop', 'price' => 1200, 'in_stock' => true],
    ['name' => 'Mouse', 'price' => 25, 'in_stock' => true],
    ['name' => 'Keyboard', 'price' => 75, 'in_stock' => false],
    ['name' => 'Monitor', 'price' => 300, 'in_stock' => true],
]);

$maxPrice = 100;

// Your code here

Hint

Chain two where calls on $products. First filter in_stock equals true, then filter price less than $maxPrice.

4

Return the filtered products

Return the $filteredProducts collection so it can be used to display the filtered product list.

Laravel

$products = collect([
    ['name' => 'Laptop', 'price' => 1200, 'in_stock' => true],
    ['name' => 'Mouse', 'price' => 25, 'in_stock' => true],
    ['name' => 'Keyboard', 'price' => 75, 'in_stock' => false],
    ['name' => 'Monitor', 'price' => 300, 'in_stock' => true],
]);

$maxPrice = 100;

$filteredProducts = $products->where('in_stock', true)->where('price', '<', $maxPrice);

// Your code here

Hint

Use return $filteredProducts; to send back the filtered collection.

Practice

1. What does the where clause do in a Laravel query?

easy

A. It sorts records in ascending order.

B. It filters records based on a condition.

C. It deletes records from the database.

D. It joins two tables together.

Solution

1. Step 1: Understand the purpose of where clause

   The where clause is used to filter database records by specifying conditions.

2. Step 2: Compare with other options

   Sorting, deleting, and joining are different operations not done by where.

3. Final Answer:

   It filters records based on a condition. -> Option B

4. Quick Check:

   Where clause = filter condition [OK]

Hint: Where means filter records by condition [OK]

Common Mistakes:

• Confusing where with orderBy for sorting
• Thinking where deletes records
• Mixing where with join operations

2. Which of the following is the correct syntax to get users with age 25 using Laravel's query builder?

easy

A. User::where('age' => 25)->get();

B. User::where('age' == 25)->get();

C. User::where(age, 25)->get();

D. User::where('age', '=', 25)->get();

Solution

1. Step 1: Recall correct where syntax

   The correct syntax uses three parameters: column, operator, value. Operator '=' is optional but valid.

2. Step 2: Check each option

   User::where('age', '=', 25)->get(); uses correct syntax. User::where('age' == 25)->get(); uses '==' inside where which is invalid. User::where(age, 25)->get(); uses unquoted column name causing undefined constant. User::where('age' => 25)->get(); uses '=>' which is wrong.

3. Final Answer:

   User::where('age', '=', 25)->get(); -> Option D

4. Quick Check:

   Correct where syntax = User::where('age', '=', 25)->get(); [OK]

Hint: Use where('column', '=', value) for filtering [OK]

Common Mistakes:

• Using '==' instead of ',' in where
• Forgetting quotes around column name
• Using '=>' instead of ',' in parameters

3. What will be the result of this Laravel query?

Product::where('price', '>', 100)->where('stock', '>=', 10)->get();

medium

A. All products with price > 100 and stock >= 10

B. All products with price > 100 or stock >= 10

C. All products with price <= 100 and stock < 10

D. Syntax error due to multiple where clauses

Solution

1. Step 1: Understand chaining of where clauses

   Chaining multiple where clauses applies AND logic between conditions.

2. Step 2: Analyze the conditions

   It filters products where price is greater than 100 AND stock is at least 10.

3. Final Answer:

   All products with price > 100 and stock >= 10 -> Option A

4. Quick Check:

   Multiple where = AND filter [OK]

Hint: Multiple where clauses combine with AND logic [OK]

Common Mistakes:

• Assuming where clauses combine with OR by default
• Thinking multiple where cause syntax error
• Confusing comparison operators

4. Identify the error in this Laravel query:

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

medium

A. Missing semicolon at the end

B. Incorrect method name, should be filter

C. No error, query is correct

D. Missing operator in where clause

Solution

1. Step 1: Check where clause parameters

   The where method accepts two parameters: column and value (assumes =), or three: column, operator, value.

2. Step 2: Analyze the query

   User::where('status', 'active')->get(); uses two parameters correctly, assuming status = 'active'.

3. Final Answer:

   No error, query is correct -> Option C

4. Quick Check:

   where needs column and value or operator [OK]

Hint: where needs column and value or operator [OK]

Common Mistakes:

• Thinking where always requires explicit operator
• Confusing method names like filter instead of where
• Ignoring Laravel's default operator '=' behavior

5. How would you write a Laravel query to get all orders where the status is 'completed' and the total is greater than 500, but only if the user is an admin? Assume you have a variable $isAdmin that is true or false.

hard

A. Order::when($isAdmin, fn($q) => $q->where('status', 'completed')->where('total', '>', 500))->get();

B. Order::where('status', 'completed')->where('total', '>', 500)->get();

C. Order::if($isAdmin)->where('status', 'completed')->where('total', '>', 500)->get();

D. Order::where('status', 'completed' && $isAdmin)->where('total', '>', 500)->get();

Solution

1. Step 1: Understand conditional queries in Laravel

   Laravel's when method allows adding conditions only if a boolean is true.

2. Step 2: Analyze each option

   Order::when($isAdmin, fn($q) => $q->where('status', 'completed')->where('total', '>', 500))->get(); uses when correctly to add where clauses only if $isAdmin is true. Order::where('status', 'completed')->where('total', '>', 500)->get(); always applies filters. Order::if($isAdmin)->where('status', 'completed')->where('total', '>', 500)->get(); uses invalid if method. Order::where('status', 'completed' && $isAdmin)->where('total', '>', 500)->get(); has wrong syntax mixing boolean and string.

3. Final Answer:

   Order::when($isAdmin, fn($q) => $q->where('status', 'completed')->where('total', '>', 500))->get(); -> Option A

4. Quick Check:

   Use when() for conditional where clauses [OK]

Hint: Use when() to add where only if condition true [OK]

Common Mistakes:

• Applying where clauses unconditionally
• Using non-existent if() method on query builder
• Incorrect syntax mixing booleans inside where