【ElasticSearch（五）进阶】两种_search检索方式，match_all检索，Query DSL基本使用
一、导入测试数据
ElasticSearch官方为我们准备了一部分测试数据供调试使用，我们可以Kinaba内进行数据导入处理
1.获取数据
https://download.elastic.co/demos/kibana/gettingstarted/accounts.zip
2.执行批量添加
http://localhost:5601中选择Kibana，选择侧边栏的Dev Tools
POST /bank/account/_bulk
后面粘贴刚才下载的数据
二、_search检索
ES支持两种基本方式检索：
一个是通过使用 REST request URI发送搜索参数(uri+检索参数)
另一个是通过使用 REST request body来发送它们(uri请求体)
【例子1】
GET /bank/_search?q=*&sort=account_number:asc
q=*表示全部搜索
sort=account_number:asc：根据account_number排序，是升序排序
返回结果：
结果并不会返回所有数据，只返回10条数据，类似于分页
took：检索花费时间
timed_out：检索是否超时
_shards：集群情况下，每个分片都为检索做了什么操作
hits：命中的记录
total.value：总记录的数量
max_score：最相关文档的得分
hits：所有命中的记录
{
"took" : 5,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 1000,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "bank",
"_type" : "account",
"_id" : "0",
"_score" : null,
"_source" : {
"account_number" : 0,
"balance" : 16623,
"firstname" : "Bradshaw",
"lastname" : "Mckenzie",
"age" : 29,
"gender" : "F",
"address" : "244 Columbus Place",
"employer" : "Euron",
"email" : "bradshawmckenzie@euron.com",
"city" : "Hobucken",
"state" : "CO"
},
"sort" : [
0
]
},
{
"_index" : "bank",
"_type" : "account",
"_id" : "1",
"_score" : null,
"_source" : {
"account_number" : 1,
"balance" : 39225,
"firstname" : "Amber",
"lastname" : "Duke",
"age" : 32,
"gender" : "M",
"address" : "880 Holmes Lane",
"employer" : "Pyrami",
"email" : "amberduke@pyrami.com",
"city" : "Brogan",
"state" : "IL"
},
"sort" : [
1
]
},
。。。
{
"_index" : "bank",
"_type" : "account",
"_id" : "9",
"_score" : null,
"_source" : {
"account_number" : 9,
"balance" : 24776,
"firstname" : "Opal",
"lastname" : "Meadows",
"age" : 39,
"gender" : "M",
"address" : "963 Neptune Avenue",
"employer" : "Cedward",
"email" : "opalmeadows@cedward.com",
"city" : "Olney",
"state" : "OH"
},
"sort" : [
9
]
}
]
}
}
【例子2】
先按照account_number进行降序，
query：查询条件
match_all：匹配所有
sort：排序条件
"account_number": "desc"先按照account_number进行降序排列
"balance": "desc"：如果account_number相同，就按照balance进行降序
GET bank/_search
{
"query": {
"match_all": {}
},
"sort": [
{
"account_number": "desc"
},
{
"balance": "desc"
}
]
}
返回结果：
{
"took" : 11,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 1000,
"relation" : "eq"
},
"max_score" : null,
"hits" : [
{
"_index" : "bank",
"_type" : "account",
"_id" : "999",
"_score" : null,
"_source" : {
"account_number" : 999,
"balance" : 6087,
"firstname" : "Dorothy",
"lastname" : "Barron",
"age" : 22,
"gender" : "F",
"address" : "499 Laurel Avenue",
"employer" : "Xurban",
"email" : "dorothybarron@xurban.com",
"city" : "Belvoir",
"state" : "CA"
},
"sort" : [
999,
6087
]
},
{
"_index" : "bank",
"_type" : "account",
"_id" : "998",
"_score" : null,
"_source" : {
"account_number" : 998,
"balance" : 16869,
"firstname" : "Letha",
"lastname" : "Baker",
"age" : 40,
"gender" : "F",
"address" : "206 Llama Court",
"employer" : "Dognosis",
"email" : "lethabaker@dognosis.com",
"city" : "Dunlo",
"state" : "WV"
},
"sort" : [
998,
16869
]
},
。。。
]
}
}
上面这种 查询条件 写成 请求体 的方式，就称为Query DSL。
三、Query DSL
1.基本语法格式
ElasticSearch提供了一个可以执行查询的Json风的DSL（domain-specific language 领域特定语言)，这被称为 Query DSL。
该查询语言非常全面,并且刚开始的时候感觉有点复杂,真正学好它的方法是从一些基础的示例开始的。
【例子1】
一个查询语句 的典型结构：
{
QUERY_NAME:{
ARGUMENT:VALUE,
ARGUMENT:VALUE...
}
}
例如查询索引bank的所有数据：
GET bank/_search
{
"query": {
"match_all": {}
}
}
【例子2】
如果是针对某个字段查询，查询结构：
{
QUERY_NAME:{
FIELD NAME:{
ARGUMENI:VALUE,
ARGUMENT:VALUE...
}
}
}
按照 balance 降序查询：
GET bank/_search
{
"query": {
"match_all": {}
},
"sort": [
{
"balance": {
"order": "desc"
}
}
]
}
其中
"balance": {
"order": "desc"
}
可以简写为：
"balance": "desc"
【例子3】
from：从查询到的第一条记录开始
size：共显示5条
GET /bank/_search
{
"query":{
"match_all": {}
},
"sort":[
{
"balance": "desc"
}
],
"from": 0,
"size": 5
}
返回的记录原本默认是10条，现在确实只有5条了
【例子4】
"_source": ["balance", "account_number"]：只显示字段balance和account_number。相当于筛选字段。
GET bank/_search
{
"query": {
"match_all": {}
},
"sort": [
{
"balance": {
"order": "desc"
}
}
],
"from": 0,
"size": 5,
"_source": ["balance", "account_number"]
}