How to Enhance the Search by SKU in Magento 2 with Long Tail Search

Type SX500123 into your store's search bar when the actual SKU is SX500-123, and by default Magento returns nothing. Long tail search fixes exactly this: it's a feature in our Elastic Search Ultimate, Sphinx Search Ultimate, and Advanced Sphinx Search Pro modules that treats a missing hyphen, a stray space, or a forward slash as the same search query.

However, we've noticed that many of our customers aren’t sure how to use the long tail search to its full potential, especially when it comes to defining search query patterns. This guide walks through how it works, how to configure it, and three common patterns for search by SKU, model number, ISBN, or similar identifiers:

1. How Magento 2 Long Tail Search Works
2. How to Set Up Magento 2 Long Tail Search
3. Examples of Improved Magento 2 SKU Search
4. Final thoughts

How Magento 2 Long Tail Search Works

Long tail search in our Magento site search modules works in many ways like a spell correction system. First you need to define a search pattern, then you manually alter characters within it. Once you set everything up, the search will regard the original pattern and the pattern with altered characters as if they were one and the same.

This feature is most useful when your visitors search by SKU, model number, ISBN, DOI, or similar product identifiers.

By default, Magento 2 search will only recognize these identifiers if the query is an exact match. Something as miniscule as a single space or a hyphen will invalidate the search. For example, if your SKU is SX500-123 and the visitor types SX500123, the search will return zero results.

This is a significant problem that can end up costing you sales. Visitors who search by such specific identifiers are often ready to make a purchase straight away.

Being unable to find what they need is all the more frustrating for them, and it makes them prone to leaving your store and shopping elsewhere – right at the end of the funnel!

Preventing this from happening in your online store is in your best interest. With the long tail search feature, you can ensure that visitors get to the product they need regardless of the format they use for their queries. This will work wonders for your store's UX and conversion rate.

You and your visitors will never again have to ask: "Why can I not search by SKU in Magento?"!

How to Set Up Magento 2 Long Tail Search

Before configuring Long Tail search expressions, make sure Magento can find your SKU at all: enable Use in Search and Visible in Advanced Search for the SKU attribute (Stores > Attributes > Product > SKU > Storefront Properties), then add SKU to the searchable attributes in System > Search Management > Search Indexes > Product Index and reindex. See the full walkthrough in our manual. Long tail search only fixes formatting mismatches – if SKU isn't searchable yet, start there first.

The Basic Principles

To configure the long tail product search, go to System > Search Management > Configuration > Mirasvit Extensions > Search Ultimate > Query handling and processing > Wildcard and query adjustments and open Long-tail search expressions. It doesn't matter whether you use Elastic Search or Sphinx Search – the feature works exactly the same in all of our modules, whether your Elastic Search Ultimate install runs on Elasticsearch or OpenSearch. You only need to configure three fields: Match Expression, Replace Expression, and Replace Char:

• Match Expression field is where you define the search query patterns. They have to match the product identifiers either as Magento indexes them or as visitors tend to write them.
• Replace Expression field is where you specify the characters inside the pattern the feature will replace. If the pattern matches what Magento indexes, you have to specify what visitors add incorrectly. If it matches what visitors often type incorrectly, you have to specify what they tend to forget.
• Replace Char field is where you set the characters that the feature will use as replacements. This field isn't mandatory. If you leave it empty, the long tail search will simply omit the characters you specified in the Replace Expression field instead. For example, SX500-123 will become SX500123. It also accepts PHP's regex backreferences ($1, $2) to reuse groups captured in Replace Expression – see the "Replacing Characters" example below.

Long tail search only applies to searchable attributes with a text, textarea, or texteditor input type, and the new expressions take effect only after you reindex.

Once you set everything up, searching by SKU in Magento 2 will treat the pattern you defined in the Match Expression field and the pattern with the altered characters exactly the same. For instance, if your SKU is SX500-123 and you replace a hyphen, typing both SX500-123 and SX500123 in the search bar will show the results for SX500-123.

That's great, but how do you define these patterns? Let's find out now:

How to Format the Patterns for the Long Tail Search

The long tail search uses the PHP flavor of Regex (short for Regular Expression), a standard pattern system for search queries. Using Regex may be daunting at first if you don't have any programming skills. However, it's not as hard as it seems. Just keep these basic principles in mind:

1. Each pattern has to be delimited by a set of slashes:

   /pattern goes here/

2. The simplest way to use Regex is to define the exact values:

   /SX500-123/

   However, that's not very useful since only an exact match will work. If you'd like to define a more abstract pattern, you have to specify a character class. Regex uses square brackets [] for that purpose. Any values you list within them will be considered valid. For example, this pattern:

   /[1at]/

   is valid for 1, a or t in the search query.

3. You can specify character ranges instead of adding all the relevant characters manually. Let's assume your SKUs only use letters and numbers. Regex is case-sensitive, so we have to type a-z, A-Z, and 0-9 within the brackets:

   /[a-zA-Z0-9]/

4. By default, a character class will only work for single-character queries. For instance, the earlier example will match 1, but not 12. If you need the pattern to match longer queries, you have to add one of the quantifiers right after the character class:

   /[a-zA-Z0-9]*/

   There are four commonly used quantifier types:

   • Match queries zero or more characters long, marked by an asterisk: *
   • Match queries one or more characters long, marked by a plus sign: +
   • Match queries zero or one character long, marked by a question mark: ?
   • Match queries a specific number of characters long, marked by a number within curly brackets: {3}

5. You can use backslashes \ to escape special characters, like forward slashes / and other backslashes. That way the long tail search will recognize them literally instead of considering them a part of Regex's syntax:

   /\//

That's it for the basics. However, keep in mind that the patterns you created have to match the relevant product variables as closely as possible, or else the feature will just pick the first qualifying string in the Magento 2 search – even if it has nothing to do with what you intended to match.

Let's narrow the pattern down. Say, all of your SKUs have a hyphen in the middle. You can just add two identical character classes and separate then with a hyphen. You don't need to escape it:

/[a-zA-Z0-9]*-[a-zA-Z0-9]*/

What if some SKUs have different characters, like forward slashes or spaces? Just add a new character class and place all the relevant characters there. You have to escape the forward slash, but spaces are always taken literally:

/[a-zA-Z0-9]*[ -\/][a-zA-Z0-9]*/

You should be able to define the majority of SKU patterns with character classes and quantifiers alone, but Regex has even more options (or tokens) you can utilize for more advanced customization.

Regex is a well-documented system, so you can easily look the tokens up online. I recommend using Regex101 in particular. This resource lets you check your pattern's syntax in real time, see how it'll work, and confirm whether it matches the queries you had in mind.

A Couple of Things to Watch Out For

Since / is the pattern's delimiter, any literal forward slash inside your expression, including one tucked inside a character class like [- /], has to be escaped as \/. Skip this and Magento rejects the save with an "Invalid regular expression" error. We've seen this trip someone up in support, and it's easy to miss since the backslash rule above is easy to forget applies inside brackets too.

It's also worth knowing what Long tail search isn't: it normalizes formatting differences within a single term, e.g. SX500-123 vs SX500123, not different terms that mean the same thing. If you need two different words to match each other, or want to group several SKUs under one search, that's a job for Synonyms instead – we've had a reader land on this exact page looking for that and need redirecting.

Examples of Improved Magento 2 SKU Search

Let's put your new-found knowledge into practice and set up your own enhancements for Magento 2 SKU search. I'll show you how to set up the long tail feature for its most common use cases: adding, replacing, and removing special characters during a search.

Adding Characters During Search

Let's assume your SKUs are separated by a hyphen, space or a forward slash, e.g. SX500/123, so you have to redirect queries where visitors type them without any separators. In this case, you'll need to use the Match Expression field to define the pattern for SKUs as Magento indexes them:

/[a-zA-Z0-9]*[ -\/][a-zA-Z0-9]*/

Add the relevant separators to the Replace Expression field:

/[ -\/]/

Leave the Replace Char field empty.

Once you set this expression up, the feature will treat the catalog searches for SX500123 the same as the searches for SX500/123.

Replacing Characters During Search

Sometimes the fix isn't stripping a separator, but inserting one. Let's assume your SKUs are indexed with a space between the letter and digit parts, e.g. SX 500, but visitors often type them solid, e.g. SX500. Stripping won't help here since there's nothing to strip in SX500, so instead of leaving Replace Char empty, use it to reference the parts your pattern captures: it accepts PHP's regex backreferences ($1, $2), not just a literal string.

In the Match Expression field, match a short run of letters followed by a run of digits:

/[a-zA-Z]{1,4}[0-9]{2,5}/

Capture both parts separately in the Replace Expression field:

/([a-zA-Z]{1,4})([0-9]{2,5})/

Reference the captured groups in the Replace Char field:

$1 $2

That way, the feature will treat search queries for SX500 the same as SX 500, GLX11 the same as GLX 11, and so on.

Removing Characters During Search

Let's assume your SKUs are written without any special characters, e.g. SX500123, so you have to redirect queries where visitors type them with a space, a hyphen, or a forward slash. In this case, we'll need to use the Match Expression field to define the pattern for SKUs as visitors type them.

Add the SKU pattern with the separators to the Match Expression field:

/[a-zA-Z0-9]*[ -\/][a-zA-Z0-9]*/

Add the separators to the Replace Expression field:

/[ -\/]/

Leave the Replace Char field empty.

That way, the feature will treat searches for SX500-123 the same as searches for SX500123.

Long tail search can help you enhance your Magento site search even more. For instance, it's possible to set up a long tail search for arbitrarily divided SKUs, e.g. SX series 500 model 123. However, this requires deeper Regex knowledge. If you'd like to implement something similar, you should consult with your developer as to the best way to set it up.

Final thoughts

Magento 2 long tail search fixes a narrow but costly problem: shoppers who know exactly what they want, down to the SKU, walking away because a hyphen or space didn't match. Set up a Match Expression, Replace Expression, and (optionally) a Replace Char, and the feature redirects incorrectly formatted queries to the right product automatically – the three worked examples above cover adding and removing separators, plus reformatting SKUs with regex backreferences, whichever direction your SKUs need.

It's built on the PHP flavor of Regex. If you want to go beyond the basics covered here, Regex101 is a good next stop.