How to get column value by another column value?

Question

I have table called my_table.

In my_table I have got 4 columns:

ID which is primary and auto increment, name, some_text, serial_number(int).

I want to get only those some_text fields which match with serial_number(int).

For example, if serial_number(int) value is '1', I need to get all those some_text fields which are in the same row with serial_number(int) which values are '1'.

Answer 1

You can directly get custom table using objectmanager concept,

    $objectManager =   \Magento\Framework\App\ObjectManager::getInstance();
    $connection = $objectManager->get('Magento\Framework\App\ResourceConnection')->getConnection('\Magento\Framework\App\ResourceConnection::DEFAULT_CONNECTION'); 
    $result1 = $connection->fetchAll("SELECT * FROM my_table");
echo "<pre>";print_r($result1);

Or

This is proper way using block:

public function __construct(
    Context $context,
    \Namespace\Module\Model\ModuleFactory $modelFactory,
    array $data = array()
) {
    $this->_modelFactory = $modelFactory;
    parent::__construct($context, $data);
}

You can get collection by factory methods:

public function getCollection(){
     $this->_modelFactory->create()->getCollection()
                      ->addFieldToFilter('serial_number',array('eq' =>'1'));
}

Answer 2

Try this to get collection,

In your block add the below code

<?php                                                                 
namespace Vendor\Module\Block;                                              
use Magento\Framework\View\Element\Template;                              
class Block_Name extends Template{
public function __construct(
    \Vendor\Module\Model\model_nameFactory $collectionFactory
) {
    $this->collectionFactory = $collectionFactory;
}

public function getCollection($productId = '')
{
    $collection = $this->collectionFactory->create()->getCollection()->addFieldToFilter('serial_number', array(
        'eq' => '1'
    ));
    //$this->collectionFactory->create()->getCollection()->addFieldToFilter('serial_number', '1');
    $getCollection = array();
    foreach ($collection as $item) {
        $getCollection[] = $item->getSomeText();  //Get some text
    }
    return $getCollection;
}}

Hope it helps :)