# NGram search troubles(Is it possible to match entire string) **URL:** \ **Category:** Elasticsearch\ **Created:** [August 6, 2019, 10:45pm UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111 "2019-08-06T22:45:51Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![N\_Antech](https://avatars.discourse-cdn.com/v4/letter/n/898d66/32.png) [@N\_Antech](https://discuss.elastic.co/u/N_Antech)\ **Post date:** [August 6, 2019, 10:45pm UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111/1 "2019-08-06T22:45:52Z")
I am almost positive that this is a simple misunderstanding on my part as I'm very new to Elasticsearch. I am trying to implement a substring matching search using ngrams. I've got it set as max\_ngram\_diff of 10. My setup looks something like: ``` "filter": { "barcode_filter": { "type": "nGram", "min_gram": "4", "max_gram": "14" } }, "analyzer": { "barcode_filter_analyzer": { "filter": [ "lowercase", "barcode_filter" ], "type": "custom", "tokenizer": "standard" } } ``` My field is defined as barcode with analyzer set to barcode\_filter\_analyzer. My goal is to be able to find substrings. So something like "V741" should find every barcode with that substring. Something like "ZR000041" should also find every barcode containing that entire substring. While the second example will find every barcode containing the entire substring, it also finds every barcode containing "0000" for example. My initial thought was to use the score but that doesn't seem to work as a barcode like 00000000000101 will end up having a very high score. Is there any good way to require that the entire query string be found? This is currently only in testing on my PC so anything requiring scrapping and restarting the index is not a big deal so if I'm approaching this in entirely the wrong way I'm happy to adjust. Any help at all would be greatly appreciated! ---
**Author:** ![spinscale](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/spinscale/32/25011_2.png) [@spinscale](https://discuss.elastic.co/u/spinscale)\ **Post date:** [August 7, 2019, 7:49am UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111/2 "2019-08-07T07:49:12Z")
hey, so the reason for this behaviour is, that by configuring a ngram filter in your mapping, this filter will also be used when querying data. This means a string like `ZR000041`, will be depicted into ngrams on the query side as well. See this example ```auto DELETE test PUT test { "mappings": { "properties": { "my_field": { "type": "text", "analyzer": "barcode_filter_analyzer", "fields": { "keyword" : { "type" : "keyword" } } } } }, "settings": { "analysis": { "filter": { "barcode_filter": { "type": "nGram", "min_gram": "4", "max_gram": "5" } }, "analyzer": { "barcode_filter_analyzer": { "filter": [ "lowercase", "barcode_filter" ], "type": "custom", "tokenizer": "standard" } } } } } GET test/_analyze { "text": "ZR000041", "analyzer": "barcode_filter_analyzer" } PUT test/_doc/2 { "my_field": "ZR000042" } PUT test/_doc/1?refresh=true { "my_field": "ZR000041" } # finds only one product GET test/_search { "query": { "match": { "my_field": { "query": "0041" } } } } # finds both products GET test/_search { "query": { "match": { "my_field": { "query": "ZR000041", "operator": "and" } } } } # favor exact match GET test/_search { "query": { "multi_match": { "query": "ZR000041", "fields": ["my_field", "my_field.keyword^2"] } } } ``` One last thing in order to understand scoring is to use the `explain: true` parameter in your search, as this will show you the final lucene query. ```auto GET test/_search { "explain": true, "query": { "match": { "my_field": { "query": "ZR000041" } } } } ``` Hope this helps... --Alex ---
**Author:** ![abdon](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/abdon/32/9195_2.png) [@abdon](https://discuss.elastic.co/u/abdon)\ **Post date:** [August 7, 2019, 3:03pm UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111/3 "2019-08-07T15:03:13Z")
To add to Alex' explanation here, one solution could be to provide a search analyzer that does not apply the ngram filter to the query terms. You could do that by configuring a `search_analyzer` in your mapping, or by providing an `analyzer` in your query: ```auto GET test/_search { "query": { "match": { "my_field": { "query": "ZR000041", "analyzer": "standard" } } } } ``` ---
**Author:** ![N\_Antech](https://avatars.discourse-cdn.com/v4/letter/n/898d66/32.png) [@N\_Antech](https://discuss.elastic.co/u/N_Antech)\ **Post date:** [August 7, 2019, 3:36pm UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111/4 "2019-08-07T15:36:27Z")
Thanks Alex, I figured that was what was happening but was having trouble wording it! Thanks for the tip on the explain, I'd not seen that before! ---
**Author:** ![N\_Antech](https://avatars.discourse-cdn.com/v4/letter/n/898d66/32.png) [@N\_Antech](https://discuss.elastic.co/u/N_Antech)\ **Post date:** [August 7, 2019, 4:03pm UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111/5 "2019-08-07T16:03:52Z")
Abdon, this seems to do exactly what I wanted. Thank you! ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [September 4, 2019, 4:03pm UTC](https://discuss.elastic.co/t/ngram-search-troubles-is-it-possible-to-match-entire-string/194111/6 "2019-09-04T16:03:58Z")
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