In this post we are discussing about the mysql queries in magento2 that we can execute directly without using model

In Magento 1 it uses two resources one for read and another for write, and the scenario in Magento 2 is different, in this we have only one resource connection that can handle both read and write

Here is how we can do it

$objectManager = \Magento\Framework\App\ObjectManager::getInstance(); // Instance of object manager
$resource = $objectManager->get('Magento\Framework\App\ResourceConnection');
$connection = $resource->getConnection();
$tableName = $resource->getTableName('sms'); //gives table name with prefix
 
//Select Data from table
$sql = "Select * FROM " . $tableName;
$result = $connection->fetchAll($sql); // gives associated array, table fields as key in array.
 
//Delete Data from table
$sql = "Delete FROM " . $tableName." Where sms_id = 1";
$connection->query($sql);
 
//Insert Data into table
$sql = "Insert Into " . $tableName . " (sms_id, destination, message) Values ('','944740850','Test')";
$connection->query($sql);
 
//Update Data into table
$sql = "Update " . $tableName . "Set destination = '9447408507' where sms_id = 1";
$connection->query($sql);

This is how we can do Direct Mysql Query without using model in Magento2