Raw expressions in Laravel

Introduction

Raw expressions let you write database commands exactly as you want without Laravel changing them. This helps when you need special SQL parts that Laravel doesn't handle automatically.

When you want to use SQL functions like NOW() or COUNT() directly in your query.

When you need to write a custom SQL snippet that Laravel's query builder can't create.

When you want to avoid Laravel escaping or modifying a part of your query.

When you want to use database-specific commands or operators not supported by Laravel.

Syntax

Laravel

DB::raw('your SQL expression here')

Use DB::raw() inside Laravel's query builder to insert raw SQL.

Be careful to avoid SQL injection by not inserting user input directly inside raw expressions.

Examples

This counts all users and returns the count with the name user_count.

Laravel

DB::table('users')->select(DB::raw('COUNT(*) as user_count'))->get();

This uses a raw WHERE clause to get orders with price greater than 100.

Laravel

DB::table('orders')->whereRaw('price > 100')->get();

This selects product names and adds the current database time as current_time.

Laravel

DB::table('products')->select('name', DB::raw('NOW() as current_time'))->get();

Sample Program

This example gets all users and shows their names plus the uppercase version using a raw SQL function UPPER(). It prints each user's name and uppercase name.

Laravel

<?php
use Illuminate\Support\Facades\DB;

$results = DB::table('users')
    ->select('name', DB::raw('UPPER(name) as uppercase_name'))
    ->get();

foreach ($results as $user) {
    echo "Name: {$user->name}, Uppercase: {$user->uppercase_name}\n";
}

Important Notes

Always sanitize or avoid inserting user input directly into raw expressions to prevent SQL injection.

Raw expressions bypass Laravel's query builder protections, so use them only when necessary.

You can use raw expressions in select, where, orderBy, and other query builder methods.

Summary

Raw expressions let you write exact SQL inside Laravel queries.

Use DB::raw() to add raw SQL safely in your queries.

Be careful with raw expressions to avoid security risks.

Practice

1. What is the primary purpose of using DB::raw() in Laravel queries?

easy

A. To insert raw SQL expressions directly into the query builder

B. To automatically escape all user inputs

C. To convert Eloquent models into arrays

D. To cache query results for faster access

Solution

1. Step 1: Understand the role of DB::raw()

   DB::raw() allows you to write raw SQL expressions inside Laravel's query builder without modification.

2. Step 2: Compare with other options

   Options B, C, and D describe different Laravel features unrelated to raw SQL expressions.

3. Final Answer:

   To insert raw SQL expressions directly into the query builder -> Option A

4. Quick Check:

   DB::raw() = raw SQL insertion [OK]

Hint: DB::raw() means write SQL exactly as is inside queries [OK]

Common Mistakes:

• Thinking DB::raw() escapes inputs automatically
• Confusing DB::raw() with model conversion
• Assuming DB::raw() caches queries

2. Which of the following is the correct syntax to use DB::raw() in a Laravel query builder to select the current date?

easy

A. DB::table('users')->select(DB::raw('CURRENT_DATE'))->get();

B. DB::table('users')->select('CURRENT_DATE')->get();

C. DB::table('users')->selectRaw('CURRENT_DATE')->get();

D. DB::table('users')->selectRaw(DB::raw('CURRENT_DATE'))->get();

Solution

1. Step 1: Identify correct raw expression usage

   DB::raw() wraps the raw SQL string inside select() to insert it as is.

2. Step 2: Analyze other options

   DB::table('users')->select('CURRENT_DATE')->get(); treats 'CURRENT_DATE' as a column name, not raw SQL. DB::table('users')->selectRaw('CURRENT_DATE')->get(); uses selectRaw() correctly but without DB::raw(), which is valid but not the exact syntax asked. DB::table('users')->selectRaw(DB::raw('CURRENT_DATE'))->get(); nests DB::raw() inside selectRaw(), which is incorrect.

3. Final Answer:

   DB::table('users')->select(DB::raw('CURRENT_DATE'))->get(); -> Option A

4. Quick Check:

   Use DB::raw() inside select() for raw SQL [OK]

Hint: Use DB::raw('SQL') inside select() for raw SQL [OK]

Common Mistakes:

• Using select() with string instead of DB::raw()
• Confusing selectRaw() and DB::raw() usage
• Nesting DB::raw() inside selectRaw() incorrectly

3. What will be the output of the following Laravel query?

DB::table('orders')
  ->select('id', DB::raw('price * quantity AS total'))
  ->where('status', 'completed')
  ->get();

medium

A. An empty collection because raw expressions are not supported in where clauses

B. A syntax error because raw expressions cannot have aliases

C. A collection of orders with id and a calculated total price (price * quantity)

D. A collection with only id and price fields, ignoring quantity

Solution

1. Step 1: Understand the select with DB::raw()

   The query selects 'id' and a raw SQL expression calculating 'price * quantity' as 'total'. This is valid and returns those fields.

2. Step 2: Check the where clause and output

   The where clause filters orders with status 'completed'. The output is a collection of matching orders with 'id' and 'total' fields.

3. Final Answer:

   A collection of orders with id and a calculated total price (price * quantity) -> Option C

4. Quick Check:

   DB::raw() with alias returns calculated fields [OK]

Hint: DB::raw() can calculate fields with aliases in select [OK]

Common Mistakes:

• Thinking raw expressions cannot have aliases
• Assuming raw expressions affect where clause support
• Ignoring the calculated field in output

4. Identify the error in this Laravel query using raw expressions:

DB::table('users')
  ->where(DB::raw('LENGTH(name)'), '>', 5)
  ->get();

medium

A. Raw expressions cannot be used inside where clauses

B. The syntax is correct; no error present

C. DB::raw() should be wrapped inside a closure for where

D. The comparison operator '>' is invalid in this context

Solution

1. Step 1: Review usage of DB::raw() in where clause

   Using DB::raw() inside where to apply SQL functions like LENGTH() is valid syntax in Laravel.

2. Step 2: Check operators and syntax

   The '>' operator is valid for comparison. No wrapping closure is required here.

3. Final Answer:

   The syntax is correct; no error present -> Option B

4. Quick Check:

   DB::raw() works in where clauses with operators [OK]

Hint: DB::raw() can be used directly in where with operators [OK]

Common Mistakes:

• Assuming raw expressions are disallowed in where
• Thinking a closure is needed for DB::raw() in where
• Misunderstanding comparison operator validity

5. You want to update all users' scores by adding 10 points using a raw SQL expression in Laravel. Which code snippet correctly achieves this safely?

hard

A. DB::table('users')->update(DB::raw('score = score + 10'));

B. DB::table('users')->update(['score' => 'score + 10']);

C. DB::table('users')->updateRaw('score = score + 10');

D. DB::table('users')->update(['score' => DB::raw('score + 10')]);

Solution

1. Step 1: Understand how to update with raw expressions

   To update a column by adding a value, use DB::raw() inside the update array to write the SQL expression.

2. Step 2: Analyze each option

   DB::table('users')->update(['score' => DB::raw('score + 10')]); correctly uses DB::raw('score + 10') as the new value. DB::table('users')->update(['score' => 'score + 10']); treats it as a string, not SQL. DB::table('users')->update(DB::raw('score = score + 10')); passes DB::raw() directly to update(), which expects an array, causing error. DB::table('users')->updateRaw('score = score + 10'); uses a non-existent updateRaw() method.

3. Final Answer:

   DB::table('users')->update(['score' => DB::raw('score + 10')]); -> Option D

4. Quick Check:

   Use DB::raw() inside update array for calculations [OK]

Hint: Use DB::raw() inside update array for arithmetic updates [OK]

Common Mistakes:

• Passing raw SQL as string without DB::raw()
• Calling non-existent updateRaw() method
• Passing DB::raw() directly instead of in array