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
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