MySQL Group By in CodeIgniter 4 Query Builder Tutorial

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CodeIgniter 4 provides the complete set of Query builder methods to use in querying database. Inside this article we will see the concept of MySQL group by in codeigniter 4 Query Builder.

In Query builder to do group by we have a method available. Group By helps us to get data with a group and even we can count number records on that group.

Learn More –

Let’s get started.


CodeIgniter 4 Installation

To create a CodeIgniter 4 setup run this given command into your shell or terminal. Please make sure composer should be installed.

$ composer create-project codeigniter4/appstarter codeigniter-4

Assuming you have successfully installed application into your local system.


.env Setup

When we install CodeIgniter 4, we will have env file at root. To use the environment variables means using variables at global scope we need to do env to .env

Either we can do via renaming file as simple as that. Also we can do by terminal command.

Open project in terminal

$ cp env .env

Above command will create a copy of env file to .env file.

Now we are ready to use environment variables.

Enable Development Mode

CodeIgniter starts up in production mode by default. You need to make it in development mode to see any error if you are working with application.

Open .env file from root.

# CI_ENVIRONMENT = production

 // Do it to 
 
CI_ENVIRONMENT = development

Now application is in development mode.


Create Database

To create a database, either we can create via Manual tool of PhpMyadmin or by means of a mysql command.

CREATE DATABASE codeigniter4_app;

Successfully, we have created a database.


Create Database Table

Next, we need a table. That table will be responsible to store data.

Let’s create a table with some columns.

CREATE TABLE `students` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `name` varchar(50) NOT NULL,
 `marks` int(11) NOT NULL,
 `status` enum('pass','fail','average') NOT NULL,
 PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Successfully, we have created a table.


Database Connection

Open .env file from project root.

Search for DATABASE. You should see the connection environment variables. Give your updated details of database connection string.

 
#--------------------------------------------------------------------
# DATABASE
#--------------------------------------------------------------------

database.default.hostname = localhost
database.default.database = codeigniter4_app
database.default.username = root
database.default.password = root
database.default.DBDriver = MySQLi
database.default.DBPrefix =
   

Now, database successfully connected with the application.


Dump Test Data To Table

Open MySQL database and run this command to insert test data into table.

--
-- Dumping data for table `students`
--

INSERT INTO `students` (`id`, `name`, `marks`, `status`) VALUES
(1, 'Student 1', 430, 'average'),
(2, 'Student 2', 520, 'pass'),
(3, 'Student 3', 390, 'fail'),
(4, 'Student 4', 510, 'pass'),
(5, 'Student 5', 430, 'average'),
(6, 'Student 6', 510, 'pass'),
(7, 'Student 7', 370, 'fail');

Here, we have few rows taking to understand the concept of group by. You can consider many more rows.


CodeIgniter 4 Group By Method

In CodeIgniter 4, groupBy() named method available to do group queries.

$builder->groupBy(ColumnName)

Example #1

Task

We want to create a group of Total students by marks wise

MySQL Query

SELECT count(id) as total_students, marks FROM students group by marks

Writing in CodeIgniter 4

We will use query builder methods for this.

<?php

namespace App\Controllers;

class Home extends BaseController
{
	public function __construct()
	{
		$this->db = db_connect();
	}

	public function index()
	{
		$builder = $this->db->table("students");

		$builder->selectCount('id','total_students');
		$builder->select('marks');
		$builder->groupBy('marks');
		$query = $builder->get();

		echo "<pre>";
		print_r($query->getResult());
      
        // To get last query executed
        // $this->db->getLastQuery();
	}
    
    //...
}

Behind the scene it will generate query as –

SELECT COUNT(`id`) AS `total_students`, `marks` FROM `students` GROUP BY `marks`

If we run this query to MySQL –

Output To Browser

Example #2

Task

We want to create a group of Total students by status wise, means how many student are pass, fail or an average.

MySQL Query

SELECT count(id) as total_students, status FROM students group by status

Writing in CodeIgniter 4

We will use query builder methods for this.

<?php

namespace App\Controllers;

class Home extends BaseController
{
	public function __construct()
	{
		$this->db = db_connect();
	}

	public function index()
	{
		$builder = $this->db->table("students");

		$builder->selectCount('id','total_students');
		$builder->select('status');
		$builder->groupBy('status');
		$query = $builder->get();

		echo "<pre>";
		print_r($query->getResult());
      
        // To get last query executed
        // $this->db->getLastQuery();
	}
    
    //...
}

Behind the scene it will generate query as –

SELECT COUNT(`id`) AS `total_students`, `status` FROM `students` GROUP BY `status`

If we run this query to MySQL –

Output To Browser

Example #3

Task

We want to create a group Total students by marks and status wise

MySQL Query

SELECT count(id) as total_students, marks, status FROM `students`group by marks, status

Writing in CodeIgniter 4

We will use query builder methods for this.

<?php

namespace App\Controllers;

class Home extends BaseController
{
	public function __construct()
	{
		$this->db = db_connect();
	}

	public function index()
	{
		$builder = $this->db->table("students");

		$builder->selectCount('id','total_students');
		$builder->select('marks, status');
		$builder->groupBy(['marks', 'status']);
		$query = $builder->get();

		echo "<pre>";
		print_r($query->getResult());
      
        // To get last query executed
        // $this->db->getLastQuery();
	}
    
    //...
}

Behind the scene it will generate query as –

SELECT COUNT(`id`) AS `total_students`, `marks`, `status` FROM `students` GROUP BY `marks`, `status`

If we run this query to MySQL –

Output To Browser

We hope this article helped you to learn MySQL Group By in CodeIgniter 4 Query Builder Tutorial in a very detailed way.

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