Magento – Search not working in special characters in magento 2

Need to some change in helper file app\code\core\Mage\CatalogSearch\Helper\Data.php

from

public function getQueryText()
{
    if (!isset($this->_queryText)) {
        $this->_queryText = $this->_getRequest()->getParam($this->getQueryParamName());   
        if ($this->_queryText === null) {
            $this->_queryText = '';
        } else {
            /* @var $stringHelper Mage_Core_Helper_String */
            $stringHelper = Mage::helper('core/string');
            $this->_queryText = is_array($this->_queryText) ? ''
                : $stringHelper->cleanString(trim($this->_queryText));

            $maxQueryLength = $this->getMaxQueryLength();
            if ($maxQueryLength !== '' && $stringHelper->strlen($this->_queryText) > $maxQueryLength) {
                $this->_queryText = $stringHelper->substr($this->_queryText, 0, $maxQueryLength);
                $this->_isMaxLength = true;
            }
        }
    }
    return $this->_queryText;
}

To

 public function getQueryText()
    {
        if (!isset($this->_queryText)) {
            $this->_queryText = $this->_getRequest()->getParam($this->getQueryParamName());   
           $this->_queryText =  preg_replace('/[^A-Za-z0-9\-\']/', '', $this->_queryText);  // escape apostraphe
            if ($this->_queryText === null) {
                $this->_queryText = '';
            } else {
                /* @var $stringHelper Mage_Core_Helper_String */
                $stringHelper = Mage::helper('core/string');
                $this->_queryText = is_array($this->_queryText) ? ''
                    : $stringHelper->cleanString(trim($this->_queryText));

                $maxQueryLength = $this->getMaxQueryLength();
                if ($maxQueryLength !== '' && $stringHelper->strlen($this->_queryText) > $maxQueryLength) {
                    $this->_queryText = $stringHelper->substr($this->_queryText, 0, $maxQueryLength);
                    $this->_isMaxLength = true;
                }
            }
        }
        return $this->_queryText;
    }

We have add only one line code in above function $this->_queryText = preg_replace('/[^A-Za-z0-9\-\']/', '', $this->_queryText);

Note: first move core file to local app\code\local\Mage\CatalogSearch\Helper\Data.php after add above change or rewrite a helper class Mage_CatalogSearch_Helper_Data to local click here to rewrite helper steps

I do not know your search engine, I suppose that you use Mysql. I cannot comment your question.

But you may try to use SolR or Elastic Search if you want to affine your search experience. It is EE feature, but you can find community module.

You need also to see which raw data is indexed to Mysql / SolR / ElasticSearch to know if the problem occurs on the index level or in the query level.

I test it with ElasticSearch and it works on my side.

I reproduice your error with Mysql search engine.

Resolution :

The data indexed (catalogsearch_fulltext_scope1) is :

*************************** 1. row ***************************
   entity_id: 45
attribute_id: 73
  data_index: Xxxx 1 DS

The SQL query for 'xxxx' request :

SELECT `main_select`.`entity_id`, MAX(score) AS `relevance` FROM (SELECT `search_index`.`entity_id`, ((0) + LEAST((MATCH (data_index) AGAINST ('xxxx*' IN BOOLEAN MODE)), 1000000) * POW(2, search_weight)) AS `score` FROM `catalogsearch_fulltext_scope1` AS `search_index` LEFT JOIN `catalog_eav_attribute` AS `cea` ON search_index.attribute_id = cea.attribute_id LEFT JOIN `cataloginventory_stock_status` AS `stock_index` ON search_index.entity_id = stock_index.product_id AND stock_index.website_id = 0 WHERE (stock_index.stock_status = 1) AND (MATCH (data_index) AGAINST ('xxxx*' IN BOOLEAN MODE))) AS `main_select` GROUP BY `entity_id` ORDER BY `relevance` DESC LIMIT 10000

The SQL query for '1 ds' request:

SELECT `main_select`.`entity_id`, MAX(score) AS `relevance` FROM (SELECT `search_index`.`entity_id`, ((0) + LEAST((MATCH (data_index) AGAINST ('1 DS' IN BOOLEAN MODE)), 1000000) * POW(2, search_weight)) AS `score` FROM `catalogsearch_fulltext_scope1` AS `search_index` LEFT JOIN `catalog_eav_attribute` AS `cea` ON search_index.attribute_id = cea.attribute_id LEFT JOIN `cataloginventory_stock_status` AS `stock_index` ON search_index.entity_id = stock_index.product_id AND stock_index.website_id = 0 WHERE (stock_index.stock_status = 1) AND (MATCH (data_index) AGAINST ('1 DS' IN BOOLEAN MODE))) AS `main_select` GROUP BY `entity_id` ORDER BY `relevance` DESC LIMIT 10000

If you check Mysql documentation, there are two parameters for Configuring Minimum and Maximum Word Length :

http://dev.mysql.com/doc/refman/5.7/en/fulltext-fine-tuning.html

So edit your my.cnf file, add these parameters :

ft_min_word_len = 1
innodb_ft_min_token_size = 1

Restart mysql

service mysql restart

Rebuild your index

bin/magento indexer:reindex

Then you will see your product on the search result page.