laravel query via sql

Laravel is a popular PHP framework that allows developers to quickly build efficient, scalable web applications. It's common to use SQL queries in Laravel when you need to query data from a database. This article will introduce how to execute SQL queries in Laravel.

Preparation

Before starting to use Laravel to execute SQL queries, we need to configure the database connection information first. In Laravel, configuring database connection information is very simple. You only need to open the .env file and modify the following information:

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=database_name
DB_USERNAME=username
DB_PASSWORD=password

We only need to modify these parameters, and Laravel will automatically connect to our database and connect using the parameters we provide. Now, we are ready to start executing SQL queries.

Executing queries

There are several ways to execute SQL queries in Laravel. Here are some commonly used methods.

Using the DB class

Laravel's DB class provides a series of methods that can be used to execute SQL queries. First, we need to introduce the DB class in our controller or model:

use IlluminateSupportFacadesDB;

Once we have introduced the DB class, we can use the following methods to execute SQL queries.

Query

The select() method of the DB class can be used to query data. Here is an example:

$data = DB::select('SELECT * FROM users');

In the above example, we query all the data in the users table and store the results in the $data variable. You can also use parameters to build queries dynamically:

$id = 1;
$data = DB::select('SELECT * FROM users WHERE id = ?', [$id]);

In the above example, we used a placeholder ? to represent the $id parameter position and then pass that parameter to the second parameter of the select() method.

Insert

The insert() method of the DB class can be used to insert data. The following is an example:

$name = 'John Doe';
$email = 'johndoe@example.com';
DB::insert('INSERT INTO users (name, email) VALUES (?, ?)', [$name, $email]);

In the above example, we inserted a piece of data into the users table.

Update

The update() method of the DB class can be used to update data. The following is an example:

$id = 1;
$email = 'johndoe@example.com';
DB::update('UPDATE users SET email = ? WHERE id = ?', [$email, $id]);

In the above example, we update the email attribute of the user with id 1 in the users table to johndoe@example.com .

Delete

The delete() method of the DB class can be used to delete data. The following is an example:

$id = 1;
DB::delete('DELETE FROM users WHERE id = ?', [$id]);

In the above example, we delete the user with id 1 in the users table.

Using Query Builder

Laravel provides another way to execute SQL queries, namely Query Builder. Query Builder is a chained query syntax that can be used to build complex query statements.

Query

The following is an example of querying data using Query Builder:

$data = DB::table('users')->get();

In the above example, we query all the data in the users table data and store the results in the $data variable. You can also use chaining methods to build queries dynamically:

$data = DB::table('users')
->select('name', 'email')
->where('id', '=', 1)
->get();

In the above example, we use the select() method to select columns in the query results, using where( ) method adds a WHERE clause.

Insert

The following is an example of inserting data using Query Builder:

$name = 'John Doe';
$email = 'johndoe@example.com';
DB::table('users')->insert([
   'name' => $name,
   'email' => $email
]);

In the above example, we inserted a row into the users table data.

Update

The following is an example of updating data using Query Builder:

$email = 'johndoe@example.com';
DB::table('users')
   ->where('id', 1)
   ->update(['email' => $email]);

In the above example, we will users The id is 1 in the table The user's email attribute is updated to johndoe@example.com.

Delete

The following is an example of deleting data using Query Builder:

DB::table('users')->where('id', 1)->delete();

In the above example, we will users The id is 1 in the table user deleted.

Summary

In this article, we introduced how to execute SQL queries in Laravel. Using DB classes or Query Builder we can easily query, insert, update and delete data. Using these features of Laravel allows us to build web applications more efficiently and reliably.

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