ElasticSearch search api的基础语法+Query DSL搜索+filter与query对比+组合查询+定位不合法的搜索

Posted 2022-06-01 transkai

一. search api的基础语法

1、search语法

 

---

GET /search

GET /index1,index2/type1,type2/search

GET /_search

"from": 0,
"size": 10

---

 

2、http协议中get是否可以带上request body

HTTP协议，一般不允许get请求带上request body，但是因为get更加适合描述查询数据的操作，因此还是这么用了

 

---

GET /_search?from=0&size=10

POST /_search

"from":0,
"size":10

---

 

碰巧，很多浏览器，或者是服务器，也都支持GET+request body模式

如果遇到不支持的场景，也可以用POST /_search

 二.Query DSL搜索

1、什么是Query DSL

 

---

GET /_search

"query":
"match_all":

---

 

2、Query DSL的基本语法

QUERY_NAME:
ARGUMENT: VALUE,
ARGUMENT: VALUE,...

QUERY_NAME:
FIELD_NAME:
ARGUMENT: VALUE,
ARGUMENT: VALUE,...

示例：

 

---

GET /test_index/test_type/_search

"query":
"match":
"test_field": "test"

---

 

3、如何组合多个搜索条件

搜索需求：title必须包含elasticsearch，content可以包含elasticsearch也可以不包含，author_id必须不为111

 

 

---

"took": 1,
"timed_out": false,
"_shards":
"total": 5,
"successful": 5,
"failed": 0
,
"hits":
"total": 3,
"max_score": 1,
"hits": [

"_index": "website",
"_type": "article",
"_id": "2",
"_score": 1,
"_source":
"title": "my hadoop article",
"content": "hadoop is very bad",
"author_id": 111

,

"_index": "website",
"_type": "article",
"_id": "1",
"_score": 1,
"_source":
"title": "my elasticsearch article",
"content": "es is very bad",
"author_id": 110

,

"_index": "website",
"_type": "article",
"_id": "3",
"_score": 1,
"_source":
"title": "my elasticsearch article",
"content": "es is very goods",
"author_id": 111


]

---

 

GET /website/article/_search

"query":
"bool":
"must": [

"match":
"title": "elasticsearch"


],
"should": [

"match":
"content": "elasticsearch"


],
"must_not": [

"match":
"author_id": 111


]

---

 

GET /test_index/_search

"query":
"bool":
"must": "match": "name": "tom" ,
"should": [
"match": "hired": true ,
"bool":
"must": "match": "personality": "good" ,
"must_not": "match": "rude": true

],
"minimum_should_match": 1

---

 

三.filter与query对比
1、filter与query示例

 

---

PUT /company/employee/2

"address":
"country": "china",
"province": "jiangsu",
"city": "nanjing"
,
"name": "tom",
"age": 30,
"join_date": "2016-01-01"

PUT /company/employee/3

"address":
"country": "china",
"province": "shanxi",
"city": "xian"
,
"name": "marry",
"age": 35,
"join_date": "2015-01-01"

---

 

搜索请求：年龄必须大于等于30，同时join_date必须是2016-01-01

 

---

GET /company/employee/_search

"query":
"bool":
"must": [

"match":
"join_date": "2016-01-01"


],
"filter":
"range":
"age":
"gte": 30

---

 

2、filter与query对比大解密

filter，仅仅只是按照搜索条件过滤出需要的数据而已，不计算任何相关度分数，对相关度没有任何影响
query，会去计算每个document相对于搜索条件的相关度，并按照相关度进行排序

一般来说，如果你是在进行搜索，需要将最匹配搜索条件的数据先返回，那么用query；如果你只是要根据一些条件筛选出一部分数据，不关注其排序，那么用filter
除非是你的这些搜索条件，你希望越符合这些搜索条件的document越排在前面返回，那么这些搜索条件要放在query中；如果你不希望一些搜索条件来影响你的document排序，那么就放在filter中即可

3、filter与query性能

filter，不需要计算相关度分数，不需要按照相关度分数进行排序，同时还有内置的自动cache最常使用filter的数据
query，相反，要计算相关度分数，按照分数进行排序，而且无法cache结果

 

四.组合查询 

1、match all

 

---

GET /_search

"query":
"match_all":

---

 

2、match

 

---

GET /_search

"query": "match": "title": "my elasticsearch article"

---

 

3、multi match

 

---

GET /test_index/test_type/_search

"query":
"multi_match":
"query": "test",
"fields": ["test_field", "test_field1"]

---

 

4、range query

 

---

GET /company/employee/_search

"query":
"range":
"age":
"gte": 30

---

 

5、term query

 

---

GET /test_index/test_type/_search

"query":
"term":
"test_field": "test hello"

---

 

6、terms query

 

---

GET /_search

"query": "terms": "tag": [ "search", "full_text", "nosql" ]

---

 

7、exist query（2.x中的查询，现在已经不提供了）

 

 

---

GET /website/article/_search

"query":
"bool":
"must": [

"match":
"title": "elasticsearch"


],
"should": [

"match":
"content": "elasticsearch"


],
"must_not": [

"match":
"author_id": 111


]

"bool":
"must": "match": "title": "how to make millions" ,
"must_not": "match": "tag": "spam" ,
"should": [
"match": "tag": "starred"
],
"filter":
"range": "date": "gte": "2014-01-01"

bool
must，must_not，should，filter

每个子查询都会计算一个document针对它的相关度分数，然后bool综合所有分数，合并为一个分数，当然filter是不会计算分数的

"bool":
"must": "match": "title": "how to make millions" ,
"must_not": "match": "tag": "spam" ,
"should": [
"match": "tag": "starred"
],
"filter":
"bool":
"must": [
"range": "date": "gte": "2014-01-01" ,
"range": "price": "lte": 29.99
],
"must_not": [
"term": "category": "ebooks"
]

GET /company/employee/_search

"query":
"constant_score":
"filter":
"range":
"age":
"gte": 30

 

 

六.定位不合法的搜索

 

 

---

GET /test_index/test_type/_validate/query?explain

"query":
"math":
"test_field": "test"

---

 

"valid": false,
"error": "org.elasticsearch.common.ParsingException: no [query] registered for [math]"

GET /test_index/test_type/_validate/query?explain

"query":
"match":
"test_field": "test"

"valid": true,
"_shards":
"total": 1,
"successful": 1,
"failed": 0
,
"explanations": [

"index": "test_index",
"valid": true,
"explanation": "+test_field:test #(#_type:test_type)"

]

一般用在那种特别复杂庞大的搜索下，比如你一下子写了上百行的搜索，这个时候可以先用validate api去验证一下，搜索是否合法