Elasticsearch简单学习8:深入了解2
2.boolean查询
● 说明：一个 bool 查询，是一个或者多个查询子句的组合
○ 总共包括 4 种⼦子句。其中 2 种会影响算分，2 种不不影响算分
● 相关性并不只是全文本检索的专利。也适⽤用于 yes | no 的⼦句，匹配的子句越多，相关性评分 越高。
如果多条查询子句被合并为一条复合查询语句 ，比如 bool 查询，
则每个查询子句计算 得出的评分会被合并到总的相关性评分中
3.boolean查询的语法
#基本语法
POST /products/_search
{
"query": {
"bool" : {
"must" : {
"term" : { "price" : "30" }
},
"filter": {
"term" : { "avaliable" : "true" }
},
"must_not" : {
"range" : {
"price" : { "lte" : 10 }
}
},
"should" : [
{ "term" : { "productID.keyword" : "JODL-X-1937-#pV7" } },
{ "term" : { "productID.keyword" : "XHDK-A-1293-#fJ3" } }
],
"minimum_should_match" :1
}
}
}● 子查询可以任意顺序出现
● 可以嵌套多个查询
● 如果你的 bool 查询中，没有 must 条件， should 中必须至少满足一条查询。
【如上：should中是一个数组，至少要满足一条。】
4.如何解决结构化查询 – “包含而不是相等”的问题
#改变数据模型，增加字段。解决数组包含而不是精确匹配的问题
POST /newmovies/_bulk
{ "index": { "_id": 1 }}
{ "title" : "Father of the Bridge Part II","year":1995, "genre":"Comedy","genre_count":1 }
{ "index": { "_id": 2 }}
{ "title" : "Dave","year":1993,"genre":["Comedy","Romance"],"genre_count":2 }
#must，有算分
POST /newmovies/_search
{
"query": {
"bool": {
"must": [
{"term": {"genre.keyword": {"value": "Comedy"}}},
{"term": {"genre_count": {"value": 1}}}
]
}
}
}增加count字段，使用boolean查询解决。
5.Filter Context – 不影响算分
#Filter。不参与算分，结果的score是0
POST /newmovies/_search
{
"query": {
"bool": {
"filter": [
{"term": {"genre.keyword": {"value": "Comedy"}}},
{"term": {"genre_count": {"value": 1}}}
]
}
}
}
#Filtering Context
POST _search
{
"query": {
"bool" : {
"filter": {
"term" : { "avaliable" : "true" }
},
"must_not" : {
"range" : {
"price" : { "lte" : 10 }
}
}
}
}
}6.Query Context – 影响算分
#Query Context
DELETE products
POST /products/_bulk
{ "index": { "_id": 1 }}
{ "price" : 10,"avaliable":true,"date":"2018-01-01", "productID" : "XHDK-A-1293-#fJ3" }
{ "index": { "_id": 2 }}
{ "price" : 20,"avaliable":true,"date":"2019-01-01", "productID" : "KDKE-B-9947-#kL5" }
{ "index": { "_id": 3 }}
{ "price" : 30,"avaliable":true, "productID" : "JODL-X-1937-#pV7" }
{ "index": { "_id": 4 }}
{ "price" : 30,"avaliable":false, "productID" : "QQPX-R-3956-#aD8" }
POST /products/_search
{
"query": {
"bool": {
"should": [
{
"term": {
"productID.keyword": {
"value": "JODL-X-1937-#pV7"}}
},
{"term": {"avaliable": {"value": true}}
}
]
}
}
}
#嵌套，实现了 should not 逻辑
POST /products/_search
{
"query": {
"bool": {
"must": {
"term": {
"price": "30"
}
},
"should": [
{
"bool": {
"must_not": {
"term": {
"avaliable": "false"
}
}
}
}
],
"minimum_should_match": 1
}
}
}7.查询语句的结构，会对相关度算分产生影响
brown和red加起来的权重只相当于quick和dog的权重。
8.控制字段的 Boosting
#通过改变boost的值，你会发现结果的排序会改变！！
POST blogs/_search
{
"query": {
"bool": {
"should": [
{"match": {
"title": {
"query": "apple,ipad",
"boost": 1.3
}
}},
{"match": {
"content": {
"query": "apple,ipad",
"boost":1.2
}
}}
]
}
}
}
DELETE news
POST /news/_bulk
{ "index": { "_id": 1 }}
{ "content":"Apple Mac" }
{ "index": { "_id": 2 }}
{ "content":"Apple iPad" }
{ "index": { "_id": 3 }}
{ "content":"Apple employee like Apple Pie and Apple Juice" }
#正常查询：吃的苹果派和苹果汁的记录显示在最前面，而不是苹果产品显示在最前面
POST news/_search
{
"query": {
"bool": {
"must": {
"match":{"content":"apple"}
}
}
}
}
#让苹果产品显示在最前面，但是，吃的苹果或苹果派不显示了！！！不合理啊！
POST news/_search
{
"query": {
"bool": {
"must": {
"match":{"content":"apple"}
},
"must_not": {
"match":{"content":"pie"}
}
}
}
}9.Boosting Query
###使用boosting优先显示苹果产品，其次显示吃的苹果！！
POST news/_search
{
"query": {
"boosting": {
"positive": {
"match": {
"content": "apple"
}
},
"negative": {
"match": {
"content": "pie"
}
},
"negative_boost": 0.5
}
}
}
https://www.elastic.co/guide/en/elasticsearch/reference/current/query-filter-context.html
https://www.elastic.co/guide/en/elasticsearch/reference/7.1/query-dsl-boosting-query.html
二、单字符串多字段查询：Dis Max Quer
https://www.elastic.co/guide/en/elasticsearch/reference/7.1/query-dsl-dis-max-query.html
1.单个字符串的查询实例
##插入数据1
PUT /blogs/_doc/1
{
"title": "Quick brown rabbits",
"body": "Brown rabbits are commonly seen."
}
##插入数据2
PUT /blogs/_doc/2
{
"title": "Keeping pets healthy",
"body": "My quick brown fox eats rabbits on a regular basis."
}
#使用should查询Brown fox
#should算分的过程只是简单的对每一个子查询的分数相加,所以,不太准
POST /blogs/_search
{
"query": {
"bool": {
"should": [
{ "match": { "title": "Brown fox" }},
{ "match": { "body": "Brown fox" }}
]
}
}
}
2.Disjunction Max Query 查询
#Disjunction Max Query 查询
POST blogs/_search
{
"query": {
"dis_max": {
"queries": [
{ "match": { "title": "Brown fox" }},
{ "match": { "body": "Brown fox" }}
]
}
}
}3.最佳字段调优
#如果分数相同怎么办？！
POST blogs/_search
{
"query": {
"dis_max": {
"queries": [
{ "match": { "title": "Quick pets" }},
{ "match": { "body": "Quick pets" }}
]
}
}
}
#如果分数相同,可以使用tie_breaker。
POST blogs/_search
{
"query": {
"dis_max": {
"queries": [
{ "match": { "title": "Quick pets" }},
{ "match": { "body": "Quick pets" }}
],
"tie_breaker": 0.2
}
}
}