Hjdcti

I need to update(increase/decrease) the price & special price by certain amount or percentage for all products in all stores.

Here is the my code but its not increase/decrease the price. I have also refered few links but not match with the needs.

<?php

error_reporting(1);
ini_set('max_execution_time', 0);
use MagentoFrameworkAppBootstrap;
require __DIR__ . '/app/bootstrap.php';

$bootstrap = MagentoFrameworkAppBootstrap::create(BP, $_SERVER);
$objectManager = $bootstrap->getObjectManager();
$objectManager = MagentoFrameworkAppObjectManager::getInstance();
$state = $objectManager->get('MagentoFrameworkAppState');
$state->setAreaCode('frontend');

$updateprice = "100";

$productFactory = $objectManager->get('MagentoCatalogModelProductFactory');
$product = $productFactory->create()->load();
$product->setPrice($updateprice);
$product->save();
?>

My version is Magento 2.2.4

Can anyone let me know how to increase/decrease the price for all products?

try my below code

<?php
ob_start();
use MagentoFrameworkAppBootstrap;
include('app/bootstrap.php');
$bootstrap = Bootstrap::create(BP, $_SERVER);
$objectManager = $bootstrap->getObjectManager();
$state = $objectManager->get('MagentoFrameworkAppState');
$state->setAreaCode('frontend');
ini_set('memory_limit', '1024M');

$updateprice = "100";
$storeId = '1'; //Store ID
$productCollection = $objectManager->create('MagentoCatalogModelResourceModelProductCollection');
$products = $productCollection->addAttributeToSelect('*')
 ->load();
foreach ($products as $_product) 
 $price = $_product->getPrice(); 
 $getSpecialPrice = $_product->getSpecialPrice(); 
 $_product->setPrice($price + $updateprice);
 $_product->setSpecialPrice($price + $updateprice);
 $_product->save();