Elasticsearch基础
下载网址：https://www.elastic.co/cn/downloads/past-releases#elasticsearch
HTML1 ：我爱我的祖国，我爱编程
HTML2 ：我爱编程，我是个快乐的小码农
正向索引
分词器将内容进行分词处理，搜索时，es数据库将想要查询的字段对分词后的结果进行挨个匹配 效率低下
倒排索引
倒排索引是按照分词与文档进行映射
插入数据
POST请求 加 _update 为修改操作，只修改指定的的字段
查询
建立索引
PUT /test_keyword
{
"mappings": {
"properties": {
"age": {
"type": "long"
},
"birthday": {
"type": "date"
},
"name": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"tags": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
普通查询
查询全部数据
GET /user/_search
{
"query": {
"match_all": {}
}
}
查询name为小胖的
GET user/_doc/_search
{
"query":{
"match":{
"name":"小胖"
}
}
}
结果
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 4,
"relation" : "eq"
},
"max_score" : 1.0498221,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : 1.0498221,
"_source" : {
"name" : "小胖",
"age" : 26,
"birthday" : "1997-04-06",
"tags" : [
"呆萌",
"认真",
"散漫"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "4",
"_score" : 0.6931471,
"_source" : {
"name" : "大胖",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"稳重",
"情商高",
"慵懒"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "2",
"_score" : 0.35667494,
"_source" : {
"name" : "小宇",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"渣男",
"心机boy",
"高富帅"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "1",
"_score" : 0.35667494,
"_source" : {
"name" : "小轩",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"小胖子",
"呆萌",
"认真"
]
}
}
]
}
}
为什么会出现这样的情况?
我们知道 字符串有两种类型 text 和 keywords ，text可用分词器进行分隔，keywords不可用分词器进行分隔
以小胖为例：
当 “小胖” 为 text 类型时 使用_analyze分词器对其进行分割
GET _analyze
{
"analyzer": "standard",
"text":"小胖"
}
结果如下
{
"tokens" : [
{
"token" : "小",
"start_offset" : 0,
"end_offset" : 1,
"type" : "" ,
"position" : 0
},
{
"token" : "胖",
"start_offset" : 1,
"end_offset" : 2,
"type" : "" ,
"position" : 1
}
]
}
当 “小胖” 为 keyword 类型时 使用_analyze分词器对其进行分割
GET _analyze
{
"analyzer": "keyword",
"text":"小胖"
}
结果如下
{
"tokens" : [
{
"token" : "小胖",
"start_offset" : 0,
"end_offset" : 2,
"type" : "word",
"position" : 0
}
]
}
由此可见当我们使用 match对 “小胖” 进行查找的时候 会查出满足以“小” 和“胖” 建立索引的数据 。
那我们用 term 进行查询的时候会查出来什么结果？
GET user/_doc/_search
{
"query":{
"term":{
"name":"小胖"
}
}
}
结果显而易见 不会出来，为什么？（ 这里先做一个补充，如果使用 match 进行匹配查询时，会先将查询字段‘小胖’进行分词 -‘小’和‘胖’，然后利用倒排索引进行查询，这也是为什么上面案例会查出来多条的原因；如果使用 term 进行查询是，不会进行分词，直接使用‘小胖’进行查询）
GET user/_doc/_search
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 0,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
}
}
查询指定列
GET user/_doc/_search
{
"query":{
"match":{
"name":"小"
}
},
"_source":["name","tags"]
}
结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 2,
"relation" : "eq"
},
"max_score" : 0.6931471,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "4",
"_score" : 0.6931471,
"_source" : {
"name" : "大胖",
"tags" : [
"稳重",
"情商高",
"慵懒"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : 0.6931471,
"_source" : {
"name" : "小胖",
"tags" : [
"呆萌",
"认真",
"散漫"
]
}
}
]
}
}
排序
GET user/_doc/_search
{
"query":{
"match":{
"name":"小"
}
},
"sort":[
{
"age":{
"order":"desc"
}
}
]
}
结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : null,
"_source" : {
"name" : "小胖",
"age" : 26,
"birthday" : "1997-04-06",
"tags" : [
"呆萌",
"认真",
"散漫"
]
},
"sort" : [
26
]
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "2",
"_score" : null,
"_source" : {
"name" : "小宇",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"渣男",
"心机boy",
"高富帅"
]
},
"sort" : [
13
]
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "1",
"_score" : null,
"_source" : {
"name" : "小轩",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"小胖子",
"呆萌",
"认真"
]
},
"sort" : [
13
]
}
]
}
}
分页
GET user/_doc/_search
{
"query":{
"match":{
"name":"小"
}
},
"sort":[
{
"age":{
"order":"desc"
}
}
],
"from":0,
"size":1
}
结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : null,
"_source" : {
"name" : "小胖",
"age" : 26,
"birthday" : "1997-04-06",
"tags" : [
"呆萌",
"认真",
"散漫"
]
},
"sort" : [
26
]
}
]
}
}
from 从第几条数据开始；size 查询后边的多少条数据
多条件匹配
同时满足 （and）
查询既满足 名称为 小胖 又满足 年龄为 26 的
GET user/_doc/_search
{
"query":{
"bool":{
"must":[
{
"match":{
"name": "小胖"
}
},
{
"match":{
"age": 26
}
}
]
}
}
}
结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : null,
"_source" : {
"name" : "小胖",
"age" : 26,
"birthday" : "1997-04-06",
"tags" : [
"呆萌",
"认真",
"散漫"
]
},
"sort" : [
26
]
}
]
}
}
或者 （or）
GET user/_doc/_search
{
"query":{
"bool":{
"should":[
{
"match":{
"name": "小胖"
}
},
{
"match":{
"age": 26
}
}
]
}
}
}
结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 4,
"relation" : "eq"
},
"max_score" : 2.049822,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : 2.049822,
"_source" : {
"name" : "小胖",
"age" : 26,
"birthday" : "1997-04-06",
"tags" : [
"呆萌",
"认真",
"散漫"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "4",
"_score" : 0.6931471,
"_source" : {
"name" : "大胖",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"稳重",
"情商高",
"慵懒"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "2",
"_score" : 0.35667494,
"_source" : {
"name" : "小宇",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"渣男",
"心机boy",
"高富帅"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "1",
"_score" : 0.35667494,
"_source" : {
"name" : "小轩",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"小胖子",
"呆萌",
"认真"
]
}
}
]
}
}
不满足
GET user/_doc/_search
{
"query":{
"bool":{
"must_not":[
{
"match":{
"age": 26
}
}
]
}
}
}
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : 0.0,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "2",
"_score" : 0.0,
"_source" : {
"name" : "小宇",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"渣男",
"心机boy",
"高富帅"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "1",
"_score" : 0.0,
"_source" : {
"name" : "小轩",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"小胖子",
"呆萌",
"认真"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "4",
"_score" : 0.0,
"_source" : {
"name" : "大胖",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"稳重",
"情商高",
"慵懒"
]
}
}
]
}
}
过滤
GET user/_doc/_search
{
"query":{
"bool":{
"must":[
{
"match":{
"name":"胖"
}
}
],
"filter":{
"range":{
"age":{
"gt":20,
"lt":26
}
}
}
}
}
}
结果 ：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 0,
"relation" : "eq"
},
"max_score" : null,
"hits" : [ ]
}
}
lt 小于 ；lte 小于等于 ; gt 大于； gte大于等于
数组类型多条件匹配
GET user/_doc/_search
{
"query":{
"bool":{
"must":[
{
"match":{
"tags":"呆萌 情商" //空格分开 多条件匹配
}
}
]
}
}
}
结果：
{
"took" : 0,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 3,
"relation" : "eq"
},
"max_score" : 2.4079456,
"hits" : [
{
"_index" : "user",
"_type" : "_doc",
"_id" : "4",
"_score" : 2.4079456,
"_source" : {
"name" : "大胖",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"稳重",
"情商高",
"慵懒"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "3",
"_score" : 1.4723402,
"_source" : {
"name" : "小胖",
"age" : 26,
"birthday" : "1997-04-06",
"tags" : [
"呆萌",
"认真",
"散漫"
]
}
},
{
"_index" : "user",
"_type" : "_doc",
"_id" : "1",
"_score" : 1.3862942,
"_source" : {
"name" : "小轩",
"age" : 13,
"birthday" : "1997-04-06",
"tags" : [
"小胖子",
"呆萌",
"认真"
]
}
}
]
}
}