整理一篇常用的CRUD查詢語句，之前這篇檔案是在17年左右發表的，從英文翻譯過來，現在採用7.x 版本進行實驗，棄用的功能或者引數，我這邊會進行更新，一起來學習吧。
為了演示不同型別的 ElasticSearch 的查詢，我們將使用書文件資訊的集合（有以下欄位：title（標題）, authors（作者）, summary（摘要）, publish_date（釋出日期）和 num_reviews（瀏覽數））。
在這之前，首先我們應該先建立一個新的索引（index），並批量匯入一些文件：
建立索引：
PUT /bookdb_index
{ "settings": { "number_of_shards": 1 }}
批量上傳文件：
注意：現在7.x 已經啟用types 型別了，對應的操作語句也要修改下，
POST /bookdb_index/book/_bulk換成POST /bookdb_index/_bulk，然後進行操作。
POST /bookdb_index/_bulk
{ "index": { "_id": 1 }}
{ "title": "Elasticsearch: The Definitive Guide", "authors": ["clinton gormley", "zachary tong"], "summary" : "A distibuted real-time search and analytics engine", "publish_date" : "2015-02-07", "num_reviews": 20, "publisher": "oreilly" }
{ "index": { "_id": 2 }}
{ "title": "Taming Text: How to Find, Organize, and Manipulate It", "authors": ["grant ingersoll", "thomas morton", "drew farris"], "summary" : "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization", "publish_date" : "2013-01-24", "num_reviews": 12, "publisher": "manning" }
{ "index": { "_id": 3 }}
{ "title": "Elasticsearch in Action", "authors": ["radu gheorge", "matthew lee hinman", "roy russo"], "summary" : "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms", "publish_date" : "2015-12-03", "num_reviews": 18, "publisher": "manning" }
{ "index": { "_id": 4 }}
{ "title": "Solr in Action", "authors": ["trey grainger", "timothy potter"], "summary" : "Comprehensive guide to implementing a scalable search engine using Apache Solr", "publish_date" : "2014-04-05", "num_reviews": 23, "publisher": "manning" }
例子：
1. 基本的匹配（Query）查詢
有兩種方式來執行一個全文匹配查詢：
- 使用 Search Lite API，它從
url中讀取所有的查詢引數 - 使用完整 JSON 作為請求體，這樣你可以使用完整的 Elasticsearch DSL
下面是一個基本的匹配查詢，查詢任一欄位包含 Guide 的記錄
GET /bookdb_index/_search?q=guide
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.28168046,
"_source": {
"title": "Elasticsearch: The Definitive Guide",
"authors": ["clinton gormley", "zachary tong"],
"summary": "A distibuted real-time search and analytics engine",
"publish_date": "2015-02-07",
"num_reviews": 20,
"publisher": "manning"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.24144039,
"_source": {
"title": "Solr in Action",
"authors": ["trey grainger", "timothy potter"],
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"publish_date": "2014-04-05",
"num_reviews": 23,
"publisher": "manning"
}
}
]
下面是完整 Search Profiler版本的查詢，生成相同的內容：
{
"query": {
"multi_match" : {
"query" : "guide",
"fields" : [ "*" ]
}
}
}
multi_match 是 match 的作為在多個欄位執行相同操作的一個速記法。fields 屬性用來指定查詢針對的欄位，*代表所有欄位，同時也可以使用單個欄位進行查詢，用逗號分隔開就可以。
在這個例子中，我們想要對文件的所有欄位進行匹配。兩個 API 都允許你指定要查詢的欄位。例如，查詢 title 欄位中包含 in Action 的書：
GET /bookdb_index/_search?q=title:in action
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.6259885,
"_source": {
"title": "Solr in Action",
"authors": [
"trey grainger",
"timothy potter"
],
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"publish_date": "2014-04-05",
"num_reviews": 23,
"publisher": "manning"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.5975345,
"_source": {
"title": "Elasticsearch in Action",
"authors": [
"radu gheorge",
"matthew lee hinman",
"roy russo"
],
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"publish_date": "2015-12-03",
"num_reviews": 18,
"publisher": "manning"
}
}
]
然而， 完整的 DSL 給予你靈活建立更復雜查詢和指定返回結果的能力（後面，我們會一一闡述）。在下面例子中，我們指定 size 限定返回的結果條數，from 指定起始位子，_source 指定要返回的欄位，以及語法高亮
POST /bookdb_index/_search
{
"query": {
"match" : {
"title" : "in action"
}
},
"size": 2,
"from": 0,
"_source": [ "title", "summary", "publish_date" ],
"highlight": {
"fields" : {
"title" : {}
}
}
}
[Results]
"hits": {
"total": 2,
"max_score": 0.9105287,
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.9105287,
"_source": {
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
},
"highlight": {
"title": [
"Elasticsearch <em>in</em> <em>Action</em>"
]
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.9105287,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"title": "Solr in Action",
"publish_date": "2014-04-05"
},
"highlight": {
"title": [
"Solr <em>in</em> <em>Action</em>"
]
}
}
]
}
注意：對於多個詞查詢，match 允許指定是否使用 and 操作符來取代預設的 or 操作符。你還可以指定 mininum_should_match 選項來調整返回結果的相關程度。具體看後面的例子。
2. 多欄位（Multi-filed）查詢
正如我們已經看到來的，為了根據多個欄位檢索（e.g. 在 title 和 summary 欄位都是相同的查詢字串的結果），你可以使用 multi_match 語句
POST /bookdb_index/_search
{
"query": {
"multi_match" : {
"query" : "elasticsearch guide",
"fields": ["title", "summary"]
}
}
}
[Results]
"hits": {
"total": 3,
"max_score": 0.9448582,
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.9448582,
"_source": {
"title": "Elasticsearch: The Definitive Guide",
"authors": [
"clinton gormley",
"zachary tong"
],
"summary": "A distibuted real-time search and analytics engine",
"publish_date": "2015-02-07",
"num_reviews": 20,
"publisher": "manning"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.17312013,
"_source": {
"title": "Elasticsearch in Action",
"authors": [
"radu gheorge",
"matthew lee hinman",
"roy russo"
],
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"publish_date": "2015-12-03",
"num_reviews": 18,
"publisher": "manning"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.14965448,
"_source": {
"title": "Solr in Action",
"authors": [
"trey grainger",
"timothy potter"
],
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"publish_date": "2014-04-05",
"num_reviews": 23,
"publisher": "manning"
}
}
]
}
注：第三條被匹配，因為 guide 在 summary 欄位中被找到。
3. Boosting
由於我們是多個欄位查詢，我們可能需要提高某一個欄位的分值。在下面的例子中，我們把 summary 欄位的分數提高三倍，為了提升 summary 欄位的重要度；因此，我們把文件 4 的相關度提高了。
POST /bookdb_index/_search
{
"query": {
"multi_match" : {
"query" : "elasticsearch guide",
"fields": ["title", "summary^3"]
}
},
"_source": ["title", "summary", "publish_date"]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.31495273,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.14965448,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.13094766,
"_source": {
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
}
}
]
注：提升不是簡簡單單通過提升因子把計算分數加成。實際的 boost 值通過歸一化和一些內部優化給出的。相關資訊請見 Elasticsearch guide
4. Bool 組合查詢
為了提供更相關或者特定的結果，AND/OR/NOT 操作符可以用來調整我們的查詢。它是以 布林查詢 的方式來實現的。布林查詢 接受如下引數：
must等同於ANDmust_not等同於NOTshould等同於OR
上面的關鍵字中在一個query中只能出現一次
打比方，如果我想要查詢這樣型別的書：書名包含 ElasticSearch 或者（OR） Solr，並且（AND）它的作者是 Clinton Gormley 不是（NOT）Radu Gheorge
POST /bookdb_index/_search
{
"query": {
"bool": {
"must": { "match": { "authors": "clinton gormely" }},
"must_not": { "match": { "authors": "radu gheorge" }},
"should": [
{ "match": { "title": "Elasticsearch" }},
{ "match": { "title": "Solr" }}
]
}
}
}
格式化版本：
POST /bookdb_index/_search
{
"query": {
"bool": {
"must": {
"match": {
"authors": "clinton gormely"
}
},
"must_not": {
"match": {
"authors": "radu gheorge"
}
},
"should": [
{
"match": {
"title": "Elasticsearch"
}
},
{
"match": {
"title": "Solr"
}
}
]
}
}
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.3672021,
"_source": {
"title": "Elasticsearch: The Definitive Guide",
"authors": [
"clinton gormley",
"zachary tong"
],
"summary": "A distibuted real-time search and analytics engine",
"publish_date": "2015-02-07",
"num_reviews": 20,
"publisher": "oreilly"
}
}
]
注：正如你所看到的，布林查詢 可以包裝任何其他查詢型別，包括其他布林查詢，以建立任意複雜或深度巢狀的查詢。
5. 模糊（Fuzzy）查詢
在進行匹配和多項匹配時，可以啟用模糊匹配來捕捉拼寫錯誤，模糊度是基於原始單詞的編輯距離來指定的。
POST /bookdb_index/_search
{
"query": {
"multi_match" : {
"query" : "comprihensiv guide",
"fields": ["title", "summary"],
"fuzziness": "AUTO"
}
},
"_source": ["title", "summary", "publish_date"],
"size": 1
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.5961596,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
}
]
注：當術語長度大於 5 個字元時，AUTO 的模糊值等同於指定值 “2”。但是，80％ 拼寫錯誤的編輯距離為 1，所以，將模糊值設定為 1 可能會提高您的整體搜尋效能。更多詳細資訊，請參閱Elasticsearch指南中的“排版和拼寫錯誤”（Typos and Misspellings）。
6. 萬用字元（Wildcard）查詢
萬用字元查詢 允許你指定匹配的模式，而不是整個術語。
？匹配任何字元*匹配零個或多個字元。
例如，要查詢名稱以字母’t’開頭的所有作者的記錄：
POST /bookdb_index/_search
{
"query": {
"wildcard" : {
"authors" : "t*"
}
},
"_source": ["title", "authors"],
"highlight": {
"fields" : {
"authors" : {}
}
}
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 1,
"_source": {
"title": "Elasticsearch: The Definitive Guide",
"authors": [
"clinton gormley",
"zachary tong"
]
},
"highlight": {
"authors": [
"zachary <em>tong</em>"
]
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "2",
"_score": 1,
"_source": {
"title": "Taming Text: How to Find, Organize, and Manipulate It",
"authors": [
"grant ingersoll",
"thomas morton",
"drew farris"
]
},
"highlight": {
"authors": [
"<em>thomas</em> morton"
]
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 1,
"_source": {
"title": "Solr in Action",
"authors": [
"trey grainger",
"timothy potter"
]
},
"highlight": {
"authors": [
"<em>trey</em> grainger",
"<em>timothy</em> potter"
]
}
}
]
7. 正則（Regexp）查詢
正則查詢 讓你可以使用比 萬用字元查詢 更復雜的模式進行查詢：
POST /bookdb_index/_search
{
"query": {
"regexp" : {
"authors" : "t[a-z]*y"
}
},
"_source": ["title", "authors"],
"highlight": {
"fields" : {
"authors" : {}
}
}
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 1,
"_source": {
"title": "Solr in Action",
"authors": [
"trey grainger",
"timothy potter"
]
},
"highlight": {
"authors": [
"<em>trey</em> grainger",
"<em>timothy</em> potter"
]
}
}
]
8. 短語匹配(Match Phrase)查詢
短語匹配查詢 要求在請求字串中的所有查詢項必須都在文件中存在，文中順序也得和請求字串一致，且彼此相連。預設情況下，查詢項之間必須緊密相連，但可以設定 slop 值來指定查詢項之間可以分隔多遠的距離，結果仍將被當作一次成功的匹配。
POST /bookdb_index/_search
{
"query": {
"multi_match" : {
"query": "search engine",
"fields": ["title", "summary"],
"type": "phrase",
"slop": 3
}
},
"_source": [ "title", "summary", "publish_date" ]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.22327082,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.16113183,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
}
]
注：在上述例子中，對於非整句型別的查詢，_id 為 1 的文件一般會比 _id 為 4 的文件得分高，結果位置也更靠前，因為它的欄位長度較短，但是對於 短語匹配型別 查詢，由於查詢項之間的接近程度是一個計算因素，因此 _id 為 4 的文件得分更高。
9. 短語字首（Match Phrase Prefix）查詢
短語字首式查詢 能夠進行 即時搜尋（search-as-you-type） 型別的匹配，或者說提供一個查詢時的初級自動補全功能，無需以任何方式準備你的資料。和 match_phrase 查詢類似，它接收slop 引數（用來調整單詞順序和不太嚴格的相對位置）和 max_expansions 引數（用來限制查詢項的數量，降低對資源需求的強度）。
POST /bookdb_index/_search
{
"query": {
"match_phrase_prefix" : {
"summary": {
"query": "search en",
"slop": 3,
"max_expansions": 10
}
}
},
"_source": [ "title", "summary", "publish_date" ]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.5161346,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.37248808,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
}
]
注：採用 查詢時即時搜尋 具有較大的效能成本。更好的解決方案是採用 索引時即時搜尋。更多資訊，請檢視 自動補齊介面（Completion Suggester API） 或 邊緣分詞器（Edge-Ngram filters）的用法。
10. 查詢字串（Query String）
查詢字串 型別（query_string）的查詢提供了一個方法，用簡潔的簡寫語法來執行 多匹配查詢、 布林查詢 、 提權查詢、 模糊查詢、 萬用字元查詢、 正則查詢 和範圍查詢。下面的例子中，我們在那些作者是 “grant ingersoll” 或 “tom morton” 的某本書當中，使用查詢項 “search algorithm” 進行一次模糊查詢，搜尋全部欄位，但給 summary 的權重提升 2 倍。
POST /bookdb_index/_search
{
"query": {
"query_string": {
"query": "(saerch~1 algorithm~1) AND (grant ingersoll) OR (tom morton)",
"fields": [
"*",
"summary^2"
]
}
},
"_source": [
"title",
"summary",
"authors"
],
"highlight": {
"fields": {
"summary": {}
}
}
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "2",
"_score": 0.14558059,
"_source": {
"summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
"title": "Taming Text: How to Find, Organize, and Manipulate It",
"authors": [
"grant ingersoll",
"thomas morton",
"drew farris"
]
},
"highlight": {
"summary": [
"organize text using approaches such as full-text <em>search</em>, proper name recognition, clustering, tagging, information extraction, and summarization"
]
}
}
]
11. 簡單查詢字串（Simple Query String）
簡單請求字串 型別（simple_query_string）的查詢是請求字串型別（query_string）查詢的一個版本，它更適合那種僅暴露給使用者一個簡單搜尋框的場景；因為它用 +/\|/- 分別替換了 AND/OR/NOT，並且自動丟棄了請求中無效的部分，不會在使用者出錯時，丟擲異常。
POST /bookdb_index/_search
{
"query": {
"simple_query_string" : {
"query": "(saerch~1 algorithm~1) + (grant ingersoll) | (tom morton)",
"fields": ["*", "summary^2"]
}
},
"_source": [ "title", "summary", "authors" ],
"highlight": {
"fields" : {
"summary" : {}
}
}
}
[Results]
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : 3.5710216,
"hits" : [
{
"_index" : "bookdb_index",
"_type" : "book",
"_id" : "2",
"_score" : 3.5710216,
"_source" : {
"summary" : "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
"title" : "Taming Text: How to Find, Organize, and Manipulate It",
"authors" : [
"grant ingersoll",
"thomas morton",
"drew farris"
]
},
"highlight" : {
"summary" : [
"organize text using approaches such as full-text <em>search</em>, proper name recognition, clustering, tagging"
]
}
}
]
}
12. 詞條（Term）/多詞條（Terms）查詢
以上例子均為 full-text(全文檢索) 的示例。有時我們對結構化查詢更感興趣，希望得到更準確的匹配並返回結果，詞條查詢 和 多詞條查詢 可幫我們實現。在下面的例子中，我們要在索引中找到所有由 Manning 出版的圖書。
POST /bookdb_index/_search
{
"query": {
"term" : {
"publisher": "manning"
}
},
"_source" : ["title","publish_date","publisher"]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "2",
"_score": 1.2231436,
"_source": {
"publisher": "manning",
"title": "Taming Text: How to Find, Organize, and Manipulate It",
"publish_date": "2013-01-24"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 1.2231436,
"_source": {
"publisher": "manning",
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 1.2231436,
"_source": {
"publisher": "manning",
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
}
]
可使用詞條關鍵字來指定多個詞條，將搜尋項用陣列傳入。
{
"query": {
"terms" : {
"publisher": ["oreilly", "packt"]
}
}
}
13. 詞條（Term）查詢 - 排序（Sorted）
詞條查詢 的結果（和其他查詢結果一樣）可以被輕易排序，多級排序也被允許：
POST /bookdb_index/_search
{
"query": {
"term": {
"publisher": "manning"
}
},
"_source": [
"publish_date",
"publisher"
],
"sort": [
{
"publish_date": {
"order": "desc"
}
}
]
}
[Results]
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "bookdb_index",
"_type" : "book",
"_id" : "3",
"_score" : null,
"_source" : {
"publisher" : "manning",
"publish_date" : "2015-12-03"
},
"sort" : [
1449100800000
]
},
{
"_index" : "bookdb_index",
"_type" : "book",
"_id" : "4",
"_score" : null,
"_source" : {
"publisher" : "manning",
"publish_date" : "2014-04-05"
},
"sort" : [
1396656000000
]
},
{
"_index" : "bookdb_index",
"_type" : "book",
"_id" : "2",
"_score" : null,
"_source" : {
"publisher" : "manning",
"publish_date" : "2013-01-24"
},
"sort" : [
1358985600000
]
}
]
}
14. 範圍查詢
另一個結構化查詢的例子是 範圍查詢。在這個例子中，我們要查詢 2015 年出版的書。
POST /bookdb_index/_search
{
"query": {
"range": {
"publish_date": {
"gte": "2015-01-01",
"lte": "2015-12-31"
}
}
},
"_source": [
"title",
"publish_date",
"publisher"
]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 1,
"_source": {
"publisher": "oreilly",
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 1,
"_source": {
"publisher": "manning",
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
}
}
]
注：範圍查詢 用於日期、數字和字串型別的欄位。
15. 過濾(Filtered)查詢
過濾查詢允許你可以過濾查詢結果。對於我們的例子中，要在標題或摘要中檢索一些書，查詢項為 Elasticsearch，但我們又想篩出那些僅有 20 個以上評論的。
新版本不支援filtered 查詢，已經棄用這個關鍵字
POST /bookdb_index/_search
{
"query": {
"filtered": {
"query" : {
"multi_match": {
"query": "elasticsearch",
"fields": ["title","summary"]
}
},
"filter": {
"range" : {
"num_reviews": {
"gte": 20
}
}
}
}
},
"_source" : ["title","summary","publisher", "num_reviews"]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.5955761,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"publisher": "oreilly",
"num_reviews": 20,
"title": "Elasticsearch: The Definitive Guide"
}
}
]
注：過濾查詢 並不強制它作用於其上的查詢必須存在。如果未指定查詢，match_all 基本上會返回索引內的全部文件。實際上，過濾只在第一次執行，以減少所需的查詢面積，並且，在第一次使用後過濾會被快取，大大提高了效能。
更新：過濾查詢 將在 ElasticSearch 5 中移除，使用 布林查詢 替代。 下面有個例子使用 布林查詢 重寫上面的例子：
POST /bookdb_index/_search
{
"query": {
"bool": {
"must" : {
"multi_match": {
"query": "elasticsearch",
"fields": ["title","summary"]
}
},
"filter": {
"range" : {
"num_reviews": {
"gte": 20
}
}
}
}
},
"_source" : ["title","summary","publisher", "num_reviews"]
}
在後續的例子中，我們將會把它使用在 多重過濾 中。
16. 多重過濾（Multiple Filters）
多重過濾 可以結合 布林查詢 使用，下一個例子中，過濾查詢決定只返回那些包含至少20條評論，且必須在 2015 年前出版，且由 O’Reilly 出版的結果。
POST /bookdb_index/_search
{
"query": {
"bool": {
"must": [
{
"match": {
"title": "Elasticsearch"
}
}
],
"filter": [
{
"term": {
"publisher": "oreilly"
}
},
{
"range": {
"publish_date": {
"gte": "2014-12-31"
}
}
}
]
}
},
"_source": [
"title",
"publisher",
"publish_date"
]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.5955761,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"publisher": "oreilly",
"num_reviews": 20,
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
}
]
17. 作用分值: 域值（Field Value）因子
也許在某種情況下，你想把文件中的某個特定域作為計算相關性分值的一個因素，比較典型的場景是你想根據普及程度來提高一個文件的相關性。在我們的示例中，我們想把最受歡迎的書（基於評論數判斷）的權重進行提高，可使用 field_value_factor 用以影響分值。
POST /bookdb_index/_search
{
"query": {
"function_score": {
"query": {
"multi_match" : {
"query" : "search engine",
"fields": ["title", "summary"]
}
},
"field_value_factor": {
"field" : "num_reviews",
"modifier": "log1p",
"factor" : 2
}
}
},
"_source": ["title", "summary", "publish_date", "num_reviews"]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.44831306,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"num_reviews": 20,
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.3718407,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"num_reviews": 23,
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.046479136,
"_source": {
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"num_reviews": 18,
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "2",
"_score": 0.041432835,
"_source": {
"summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
"num_reviews": 12,
"title": "Taming Text: How to Find, Organize, and Manipulate It",
"publish_date": "2013-01-24"
}
}
]
注1: 我們可能剛執行了一個常規的 multi_match (多匹配)查詢，並對 num_reviews 域進行了排序，這讓我們失去了評估相關性分值的好處。
注2: 有大量的附加引數可用來調整提升原始相關性分值效果的程度，比如 modifier, factor, boost_mode 等等，至於細節可在 Elasticsearch 指南中探索。
18. 作用分值: 衰變（Decay）函式
假設不想使用域值做遞增提升，而你有一個理想目標值，並希望用這個加權因子來對這個離你較遠的目標值進行衰減。有個典型的用途是基於經緯度、價格或日期等數值域的提升。在如下的例子中，我們查詢在2014年6月左右出版的，查詢項是 search engines 的書。
POST /bookdb_index/_search
{
"query": {
"function_score": {
"query": {
"multi_match" : {
"query" : "search engine",
"fields": ["title", "summary"]
}
},
"functions": [
{
"exp": {
"publish_date" : {
"origin": "2014-06-15",
"offset": "7d",
"scale" : "30d"
}
}
}
],
"boost_mode" : "replace"
}
},
"_source": ["title", "summary", "publish_date", "num_reviews"]
}
[Results]
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.27420625,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"num_reviews": 23,
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.005920768,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"num_reviews": 20,
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "2",
"_score": 0.000011564,
"_source": {
"summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
"num_reviews": 12,
"title": "Taming Text: How to Find, Organize, and Manipulate It",
"publish_date": "2013-01-24"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.0000059171475,
"_source": {
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"num_reviews": 18,
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
}
}
]
19. 函式分值: 指令碼評分
當內建的評分函式無法滿足你的需求時，還可以用 Groovy 指令碼。在我們的例子中，想要指定一個指令碼，能在決定把 num_reviews 的因子計算多少之前，先將 publish_date 考慮在內。因為很新的書也許不會有評論，分值不應該被懲罰。
評分指令碼如下：
publish_date = doc['publish_date'].value
num_reviews = doc['num_reviews'].value
if (publish_date > Date.parse('yyyy-MM-dd', threshold).getTime()) {
my_score = Math.log(2.5 + num_reviews)
} else {
my_score = Math.log(1 + num_reviews)
}
return my_score
在 script_score 引數內動態呼叫評分指令碼：
POST /bookdb_index/book/_search
{
"query": {
"function_score": {
"query": {
"multi_match" : {
"query" : "search engine",
"fields": ["title", "summary"]
}
},
"functions": [
{
"script_score": {
"params" : {
"threshold": "2015-07-30"
},
"script": "publish_date = doc['publish_date'].value; num_reviews = doc['num_reviews'].value; if (publish_date > Date.parse('yyyy-MM-dd', threshold).getTime()) { return log(2.5 + num_reviews) }; return log(1 + num_reviews);"
}
}
]
}
},
"_source": ["title", "summary", "publish_date", "num_reviews"]
}
[Results]
"hits": {
"total": 4,
"max_score": 0.8463001,
"hits": [
{
"_index": "bookdb_index",
"_type": "book",
"_id": "1",
"_score": 0.8463001,
"_source": {
"summary": "A distibuted real-time search and analytics engine",
"num_reviews": 20,
"title": "Elasticsearch: The Definitive Guide",
"publish_date": "2015-02-07"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "4",
"_score": 0.7067348,
"_source": {
"summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",
"num_reviews": 23,
"title": "Solr in Action",
"publish_date": "2014-04-05"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "3",
"_score": 0.08952084,
"_source": {
"summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",
"num_reviews": 18,
"title": "Elasticsearch in Action",
"publish_date": "2015-12-03"
}
},
{
"_index": "bookdb_index",
"_type": "book",
"_id": "2",
"_score": 0.07602123,
"_source": {
"summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",
"num_reviews": 12,
"title": "Taming Text: How to Find, Organize, and Manipulate It",
"publish_date": "2013-01-24"
}
}
]
}
注1: 要在 Elasticsearch 例項中使用動態指令碼，必須在 config/elasticsearch.yaml 檔案中啟用它；也可以使用儲存在 Elasticsearch 伺服器上的指令碼。建議看看 Elasticsearch 指南文件獲取更多資訊。
注2: 因 JSON 不能包含嵌入式換行符，請使用分號來分割語句。