Elastic search query from SQL statement with multiple WHERE clause - elasticsearch

I need Elastic Search Query based on following SQL Statement
SELECT * FROM documents
WHERE (doc_name like "%test%" OR doc_type like "%test%" OR doc_desc like "%test%) AND
user_id = 1 AND doc_category = "Utilities"

It depends on your mapping, but you can start working with something like this:
"query": {
"filtered": {
"filter": {
"bool": {
"must": [
{
"term": {
"user_id": 1
}
},
{
"term": {
"doc_category": "Utilities"
}
}
]
}
},
"query": {
"multi_match": {
"query": "test",
"fields": ["doc_name", "doc_type", "doc_desc"]
}
}
}
}

Adding to the answer given by jbasko: Doing LIKE queries in elsaticsearch very much depends on your mapping of the document fields. For example if you want the equivalent of LIKE '%test%' in elasticsearch you need to use the ngram tokenizer for it :
{
"settings": {
"analysis": {
"analyzer": {
"some_analyzer_name": {
"tokenizer": "some_tokenizer_name"
}
},
"tokenizer": {
"some_tokenizer_name": {
"type": "ngram",
"min_gram": <minimum number of characters>,
"max_gram": <maximum number of characters>,
"token_chars": [
"letter",
"digit"
]
}
}
}
...
and in the mapping of the fields use the analyzer:
"mapping":{
...
"doc_type" : {
"type" :"string",
"analyzer" : "some_analyzer_name"
},
...
"doc_type" : {
"type" :"string",
"analyzer" : "some_analyzer_name"
},
...
}
A short explanation about ngram, this tokenizer breaks the string in the fields doc_type and the others to small consecutive strings with the amount of characters you defined in settings.
i.e. an ngram with
min_gram : 1
max_gram : 3
on the string "abcd".
You'll get a collection of terms: 'a','ab','abc','b','bc','bcd','c','cd','c'. This terms will be used by elasticsearch to find the correct document using a match (or multi-match) query with inverse index.
For further reading you can search for : mapping,ngram tokenizer and termvectors in elasticsearch wiki.

Related

Search in Elasticsearch for a string containing the "not" keyword

I am using ElasticSearch on AWS (7.9 version) and I am trying to distinguish between two strings.
My main target is to split the search results on "Found" and on "Not found".
The generic question is how to search for "not" keyword.
Two example messages you can see below.
"CachingServiceOne:Found in cache - Retrieve."
"CachingServiceThree:Not found in cache - Create new."
You can use ngram tokenizer, to search for "not" on "title" field.
Adding a working example with index data, mapping, search query, and search result
Index Mapping:
{
"settings": {
"analysis": {
"analyzer": {
"my_analyzer": {
"tokenizer": "my_tokenizer"
}
},
"tokenizer": {
"my_tokenizer": {
"type": "ngram",
"min_gram": 3,
"max_gram": 5,
"token_chars": [
"letter",
"digit"
]
}
}
},
"max_ngram_diff": 10
},
"mappings": {
"properties": {
"title": {
"type": "text",
"analyzer": "my_analyzer"
}
}
}
}
Index Data:
{
"title":"CachingServiceThree:Not found in cache - Create new."
}
{
"title":"CachingServiceOne:Found in cache - Retrieve."
}
Search Query:
{
"query":{
"match":{
"title":"Not"
}
}
}
Search Result:
"hits": [
{
"_index": "67093372",
"_type": "_doc",
"_id": "2",
"_score": 0.6720003,
"_source": {
"title": "CachingServiceThree:Not found in cache - Create new."
}
}
]
Well, the problem seems to be indeed the way the default analyzer works, and not the fact that I could not search for the not word. That is why I accepted the answer. But I would like to add another take. For the sake of simplicity.
Default analyzer does not split words on :.
That means, we have to search for title:CachingServiceThree\:Not.
Where title is the field name and : must be escaped \:.
What did the trick was title:*\:Not and title:*\:Found using the KQL syntax.
Using the wildcard did the trick to fetch everything. I am wondering whether using an array of all the actual values will be quicker.
That translated through the Inspect panel into:
{
"query": {
"bool": {
"filter": [
{
"bool": {
"should": [
{
"query_string": {
"fields": [
"title"
],
"query": "*\\:Not"
}
}
],
"minimum_should_match": 1
}
}
]
}
}
}

Could I combine wildcard and fulltext search in Elasticsearch?

For example, I have some titles data in Elasticsearch likes this,
gamexxx_nightmare,
gamexxx_little_guy
Then I input
game => search out gamexxx_nightmare and gamexxx_little_guy
little guy => search out gamexxx_little_guy ?
first I think I will use a wildcard to make game match gamexxx, the second it is fulltext search?
How to combine them in one DSL??
While Jaspreet's answer is right but doesn't combine both the requirements in one query DSL as asked by OP in his question How to combine them in one DSL??.
It's an enhancement to Jaspreet's solution as I am also not using the wild-card and even avoiding the n-gram analyzer which is too costly(increases the index size) and requires re-indexing if requirement changes.
One Search query to combine both the requirement can be done as below:
Index mapping
{
"settings": {
"analysis": {
"analyzer": {
"my_analyzer": {
"tokenizer": "standard",
"char_filter": [
"replace_underscore" -->note this
]
}
},
"char_filter": {
"replace_underscore": {
"type": "mapping",
"mappings": [
"_ => \\u0020"
]
}
}
}
},
"mappings": {
"properties": {
"title": {
"type": "text",
"analyzer" : "my_analyzer"
}
}
}
}
Index your sample docs
{
"title" : "gamexxx_little_guy"
}
And
{
"title" : "gamexxx_nightmare"
}
Single Search query
{
"query": {
"bool": {
"must": [ --> note this
{
"bool": {
"must": [
{
"prefix": {
"title": {
"value": "game"
}
}
}
]
}
},
{
"bool": {
"must": [
{
"match": {
"title": {
"query": "little guy"
}
}
}
]
}
}
]
}
}
}
Result
{
"_index": "so-46873023",
"_type": "_doc",
"_id": "2",
"_score": 2.2814486,
"_source": {
"title": "gamexxx_little_guy"
}
}
Important points:
The first part of the query is prefix query, which would match the game in both the documents. (This would avoid costly regex).
The second part is allowing the full-text search, to enable this, I used custom analyzer which replaces the _ with whitespace, so you don't need expensive (n-grams in index) and simple match query would fetch the results.
Above query, returns result matching both the criteria, you can change the high level, bool clause to should from must if, you want to return matching any criteria.
NGrams have better performance than wildcards. For wild card all documents have to be scanned to see which match the pattern. Ngrams break a text in small tokens. Ex Quick Foxes will stored as [ Qui, uic, ick, Fox, oxe, xes ] depending on min_gram and max_gram size.
PUT my_index
{
"settings": {
"analysis": {
"analyzer": {
"my_analyzer": {
"tokenizer": "my_tokenizer"
}
},
"tokenizer": {
"my_tokenizer": {
"type": "ngram",
"min_gram": 3,
"max_gram": 3,
"token_chars": [
"letter",
"digit"
]
}
}
}
},
"mappings": {
"properties": {
"text":{
"type": "text",
"analyzer": "my_analyzer"
}
}
}
}
Query
GET my_index/_search
{
"query": {
"match": {
"text": "little guy"
}
}
}
If you want to go with wildcard only then you can search on not_analyzed string. This will handle spaces between words
"wildcard": {
"text.keyword": {
"value": "*gamexxx*"
}
}

Autocomplete functionality using elastic search

I have an elastic search index with following documents and I want to have an autocomplete functionality over the specified fields:
mapping: https://gist.github.com/anonymous/0609b1d110d91dceb9a90faa76d1d5d4
Usecase:
My query is of the form prefix type eg "sta", "star", "star w" .."start war" etc with an additional filter as tags = "science fiction". Also there queries could match other fields like description, actors(in cast field, not this is nested). I also want to know which field it matched to.
I investigated 2 ways for doing that but non of the methods seem to address the usecase above:
1) Suggester autocomplete:
https://www.elastic.co/guide/en/elasticsearch/reference/1.7/search-suggesters-completion.html
With this it seems I have to add another field called "suggest" replicating the data which is not desirable.
2) using a prefix filter/query:
https://www.elastic.co/guide/en/elasticsearch/reference/1.7/query-dsl-prefix-filter.html
this gives the whole document back not the exact matching terms.
Is there a clean way of achieving this, please advise.
Don't create mapping separately, insert data directly into index. It will create default mapping for that. Use below query for autocomplete.
GET /netflix/movie/_search
{
"query": {
"query_string": {
"query": "sta*"
}
}
}
I think completion suggester would be the cleanest way but if that is undesirable you could use aggregations on name field.
This is a sample index(I am assuming you are using ES 1.7 from your question
PUT netflix
{
"settings": {
"analysis": {
"analyzer": {
"prefix_analyzer": {
"tokenizer": "keyword",
"filter": [
"lowercase",
"trim",
"edge_filter"
]
},
"keyword_analyzer": {
"tokenizer": "keyword",
"filter": [
"lowercase",
"trim"
]
}
},
"filter": {
"edge_filter": {
"type": "edge_ngram",
"min_gram": 1,
"max_gram": 20
}
}
}
},
"mappings": {
"movie":{
"properties": {
"name":{
"type": "string",
"fields": {
"prefix":{
"type":"string",
"index_analyzer" : "prefix_analyzer",
"search_analyzer" : "keyword_analyzer"
},
"raw":{
"type": "string",
"analyzer": "keyword_analyzer"
}
}
},
"tags":{
"type": "string", "index": "not_analyzed"
}
}
}
}
}
Using multi-fields, name field is analyzed in different ways. name.prefix is using keyword tokenizer with edge ngram filter
so that string star wars can be broken into s, st, sta etc. but while searching, keyword_analyzer is used so that search query does not get broken into multiple small tokens. name.raw will be used for aggregation.
The following query will give top 10 suggestions.
GET netflix/movie/_search
{
"query": {
"filtered": {
"filter": {
"term": {
"tags": "sci-fi"
}
},
"query": {
"match": {
"name.prefix": "sta"
}
}
}
},
"size": 0,
"aggs": {
"unique_movie_name": {
"terms": {
"field": "name.raw",
"size": 10
}
}
}
}
Results will be something like
"aggregations": {
"unique_movie_name": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": "star trek",
"doc_count": 1
},
{
"key": "star wars",
"doc_count": 1
}
]
}
}
UPDATE :
You could use highlighting for this purpose I think. Highlight section will get you the whole word and which field it matched. You can also use inner hits and highlighting inside it to get nested docs also.
{
"query": {
"query_string": {
"query": "sta*"
}
},
"_source": false,
"highlight": {
"fields": {
"*": {}
}
}
}

How do I search for partial accented keyword in elasticsearch?

I have the following elasticsearch settings:
"settings": {
"index":{
"analysis":{
"analyzer":{
"analyzer_keyword":{
"tokenizer":"keyword",
"filter":["lowercase", "asciifolding"]
}
}
}
}
}
The above works fine for the following keywords:
Beyoncé
Céline Dion
The above data is stored in elasticsearch as beyonce and celine dion respectively.
I can search for Celine or Celine Dion without the accent and I get the same results. However, the moment I search for Céline, I don't get any results. How can I configure elasticsearch to search for partial keywords with the accent?
The query body looks like:
{
"track_scores": true,
"query": {
"bool": {
"must": [
{
"multi_match": {
"fields": ["name"],
"type": "phrase",
"query": "Céline"
}
}
]
}
}
}
and the mapping is
"mappings" : {
"artist" : {
"properties" : {
"name" : {
"type" : "string",
"fields" : {
"orig" : {
"type" : "string",
"index" : "not_analyzed"
},
"simple" : {
"type" : "string",
"analyzer" : "analyzer_keyword"
}
},
}
I would suggest this mapping and then go from there:
{
"settings": {
"index": {
"analysis": {
"analyzer": {
"analyzer_keyword": {
"tokenizer": "whitespace",
"filter": [
"lowercase",
"asciifolding"
]
}
}
}
}
},
"mappings": {
"test": {
"properties": {
"name": {
"type": "string",
"analyzer": "analyzer_keyword"
}
}
}
}
}
Confirm that the same analyzer is getting used at query time. Here are some possible reasons why that might not be happening:
you specify a separate analyzer at query time on purpose that is not performing similar analysis
you are using a term or terms query for which no analyzer is applied (See Term Query and the section title "Why doesn’t the term query match my document?")
you are using a query_string query (E.g. see Simple Query String Query) - I have found that if you specify multiple fields with different analyzers and so I have needed to separate the fields into separate queries and specify the analyzer parameter (working with version 2.0)

Ignore leading zeros with Elasticsearch

I am trying to create a search bar where the most common query will be for a "serviceOrderNo". "serviceOrderNo" is not a number field in the database, it is a string field. Examples:
000000007
000000002
WO0000042
123456789
AllTextss
000000054
000000065
000000874
The most common format is just an integer proceeded by some number of zeros.
How do I set up Elasticsearch so that searching for "65" will match "000000065"? I also want to give precedence to the "serviceOrderNo" field (which I already have working). Here is where I am at right now:
{
"query": {
"multi_match": {
"query": "65",
"fields": ["serviceOrderNo^2", "_all"],
}
}
}
One way of doing this is using the lucene flavour regular exression query:
https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-regexp-query.html
"query": {
"regexp":{
"serviceOrderNo": "[0]*65"
}
}
Also, the Query String query also supports a small set of special characters, more limited set of regular expression characters, AS WELL AS lucene regular expressions the query would look like this:
https://www.elastic.co/guide/en/elasticsearch/reference/1.x/query-dsl-query-string-query.html
"query": {
"query_string": {
"default_field": "serviceOrderNo",
"query": "0*65"
}
}
These are fairly simple Regular expressions, both saying match the character(s) contained in the brackets [0] or the character 0 unlimited times *.
If you have the ability to reindex, or haven't indexed your data yet, you also have the ability to make this easier on yourself by writing a custom analyzer. Right now, you are using the default analyzer for Strings on your serviceOrderNo field. When you index "serviceOrderNo":"00000065" ES interprets this simply as 00000065.
Your custom analyzer could tokenize this field int both "0000065" and "65", using the same regular expression. The benefit of this is that the Regex only runs once at index time, instead of every time you run your query because ES will search against both "0000065" and "65".
You can also check out the ES website documentation on Analyzers.
"settings":{
"analysis": {
"filter":{
"trimZero": {
"type":"pattern_capture",
"patterns":"^0*([0-9]*$)"
}
},
"analyzer": {
"serviceOrderNo":{
"type":"custom",
"tokenizer":"standard",
"filter":"trimZero"
}
}
}
},
"mappings":{
"serviceorderdto": {
"properties":{
"serviceOrderNo":{
"type":"String",
"analyzer":"serviceOrderNo"
}
}
}
}
One way to do this is to use an ngram token filter so that "12345" gets tokenized as:
[ 1, 2, 3, 4, 5 ]
[ 12, 23, 34, 45 ]
[ 123, 234, 345 ]
[ 12345 ]
When tokenized this way, "65" is a match for "000000065".
To set this up, create a new index that has a custom analyzer that uses an ngram filter:
POST /my-index
{
"mappings": {
"serviceorderdto": {
"properties": {
"serviceOrderNo": {
"type": "string",
"analyzer": "autocomplete"
}
}
}
},
"settings": {
"analysis": {
"filter": {
"autocomplete_filter": {
"type": "ngram",
"min_gram": 1,
"max_gram": 20
}
},
"analyzer": {
"autocomplete": {
"type": "custom",
"tokenizer": "standard",
"filter": [
"lowercase",
"autocomplete_filter"
]
}
}
}
}
}
Index some data.
Then run your query:
GET /my-index/_search
{
"query": {
"multi_match": {
"query": "55",
"fields": [
"serviceOrderNo^2",
"_all"
]
}
}
}

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