Query scopes in Laravel

Introduction

Query scopes help you reuse common database query parts easily. They keep your code clean and simple.

You want to filter users who are active in many places in your app.

You need to reuse a common condition like 'only published posts' in different queries.

You want to keep your database queries organized inside your model.

You want to avoid repeating the same query code in multiple controllers or views.

Syntax

Laravel

public function scopeName($query, $param1, $param2)
{
    return $query->where(...);
}

Scope methods always start with 'scope' followed by the scope name with first letter uppercase.

When using the scope, call it without the 'scope' prefix, like Model::name($params).

Examples

This scope filters records where the 'active' column is 1.

Laravel

public function scopeActive($query)
{
    return $query->where('active', 1);
}

This scope filters records by a given type passed as a parameter.

Laravel

public function scopeOfType($query, $type)
{
    return $query->where('type', $type);
}

Sample Program

This example shows a User model with two query scopes: active and role. You can call these scopes to filter users easily. The example prints the SQL queries generated by these scopes.

Laravel

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class User extends Model
{
    // Scope to get only active users
    public function scopeActive($query)
    {
        return $query->where('active', 1);
    }

    // Scope to get users by role
    public function scopeRole($query, $role)
    {
        return $query->where('role', $role);
    }
}

// Usage example in a controller or elsewhere
$activeUsers = User::active()->get();
$adminUsers = User::role('admin')->get();

// For demonstration, we print the SQL queries generated

echo $activeUsers->toSql() . "\n";
echo $adminUsers->toSql() . "\n";

Important Notes

Query scopes keep your queries DRY (Don't Repeat Yourself).

Scopes can accept parameters to make them flexible.

Use scopes to improve readability and maintainability of your code.

Summary

Query scopes let you reuse common query parts inside your model.

Define scopes with methods starting with 'scope' and call them without that prefix.

Scopes can take parameters to customize the query.

Practice

1. What is the main purpose of using query scopes in a Laravel model?

easy

A. To create database migrations

B. To define database table relationships

C. To handle user authentication

D. To reuse common query filters easily across different queries

Solution

1. Step 1: Understand query scopes role

   Query scopes allow you to write common query parts once and reuse them easily.

2. Step 2: Compare with other options

   Defining relationships, migrations, or authentication are unrelated to query scopes.

3. Final Answer:

   To reuse common query filters easily across different queries -> Option D

4. Quick Check:

   Query scopes = reusable query filters [OK]

Hint: Query scopes = reusable query parts in models [OK]

Common Mistakes:

• Confusing scopes with relationships
• Thinking scopes create migrations
• Mixing scopes with authentication logic

2. Which of the following is the correct way to define a query scope named active in a Laravel model?

easy

A. public function scopeActive($query) { return $query->where('status', 'active'); }

B. public function scopeActive() { return $this->where('status', 'active'); }

C. public function scope_active($query) { return $query->where('status', 'active'); }

D. public function active() { return $this->where('status', 'active'); }

Solution

1. Step 1: Recall scope method naming

   Query scopes must be prefixed with 'scope' and accept $query as first parameter.

2. Step 2: Check method signature and body

   public function scopeActive($query) { return $query->where('status', 'active'); } correctly uses 'scopeActive($query)' and returns $query with condition.

3. Final Answer:

   public function scopeActive($query) { return $query->where('status', 'active'); } -> Option A

4. Quick Check:

   Scope method = scope + $query param [OK]

Hint: Scope methods start with 'scope' and take $query param [OK]

Common Mistakes:

• Omitting $query parameter
• Using underscore in method name
• Not prefixing method with 'scope'

3. Given this scope in a Laravel model:

public function scopePopular($query) {
    return $query->where('votes', '>', 100);
}

What will User::popular()->get() return?

medium

A. All users regardless of votes

B. All users with votes less than or equal to 100

C. All users with votes greater than 100

D. Syntax error because scope is missing

Solution

1. Step 1: Understand the scope condition

   The scope filters users where 'votes' is greater than 100.

2. Step 2: Analyze the query call

   Calling User::popular()->get() applies the scope and returns matching users.

3. Final Answer:

   All users with votes greater than 100 -> Option C

4. Quick Check:

   Scope filters votes > 100 = users returned [OK]

Hint: Scope filters queries; check condition carefully [OK]

Common Mistakes:

• Confusing greater than with less than
• Assuming scope returns all records
• Thinking scope causes syntax error

4. Identify the error in this scope definition:

public function scopeRecent() {
    return $this->orderBy('created_at', 'desc');
}

medium

A. Missing $query parameter in the scope method

B. Incorrect method name, should not start with 'scope'

C. Using orderBy inside scope is not allowed

D. Missing return type declaration

Solution

1. Step 1: Check scope method signature

   Scope methods must accept $query as the first parameter to modify the query.

2. Step 2: Identify missing parameter

   The method lacks the $query parameter, so it cannot modify the query builder.

3. Final Answer:

   Missing $query parameter in the scope method -> Option A

4. Quick Check:

   Scope method needs $query param [OK]

Hint: Scope methods always need $query parameter [OK]

Common Mistakes:

• Forgetting $query parameter
• Thinking orderBy is disallowed in scopes
• Confusing method naming rules

5. You want to create a reusable scope activeAndRecent that returns users who are active and created within the last 30 days. Which of the following scope definitions is correct?

hard

A. public function scopeActiveAndRecent($query) {
return $query->where('status', 'active')
->orWhere('created_at', '>=', now()->subDays(30));
}

B. public function scopeActiveAndRecent($query) {
return $query->where('status', 'active')
->where('created_at', '>=', now()->subDays(30));
}

C. public function scopeActiveAndRecent() {
return $this->where('status', 'active')
->where('created_at', '>=', now()->subDays(30));
}

D. public function activeAndRecent($query) {
return $query->where('status', 'active')
->where('created_at', '>=', now()->subDays(30));
}

Solution

1. Step 1: Verify method signature and parameters

   The scope method must be named with 'scope' prefix and accept $query parameter.

2. Step 2: Check query conditions logic

   Use 'where' twice to combine conditions with AND logic for active status and recent date.

3. Step 3: Compare options

   public function scopeActiveAndRecent($query) { return $query->where('status', 'active') ->where('created_at', '>=', now()->subDays(30)); } correctly uses 'scopeActiveAndRecent($query)' and combines conditions with 'where'.

4. Final Answer:

   public function scopeActiveAndRecent($query) { return $query->where('status', 'active') ->where('created_at', '>=', now()->subDays(30)); } -> Option B

5. Quick Check:

   Scope with $query and AND conditions = public function scopeActiveAndRecent($query) { return $query->where('status', 'active') ->where('created_at', '>=', now()->subDays(30)); } [OK]

Hint: Use 'where' twice for AND, scope method needs $query [OK]

Common Mistakes:

• Using orWhere instead of where for AND logic
• Omitting $query parameter
• Not prefixing method with 'scope'