Elasticsearch7.X entry-learning Lesson notes ---- Search API's (Request Body Search and DSL Profile)

Original: Elasticsearch7.X entry-learning Lesson notes ---- Search API's (Request Body Search and DSL Profile)

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Elasticsearch suggested that we try to use Request Body query syntax in this way to support richer.

Common Syntax

     First look at a simple example. This example queries two indexes (movies and 404_idx) of all documents. Theoretically, if 404_idx index does not exist, Elasticsearch returns an error. However, due to ignore_unavailable parameters, execution will ignore the index unavailable.

   
   
# ignore_unavailable= true，可以忽略尝试访问不存在的索引“ 404_idx”导致的报错
POST /movies, 404_idx/_search?ignore_unavailable= true
{
"profile": true,
"query": {
"match_all": {}
}
}
  
  

 1 from / sizepagination

    We can also use  from / size to implement paging combination.

   
   
POST /movies/_search
{
"from": 0,
"size": 20,
"query": {
"match_all": {}
}
}
  
  

2 sortSorting

     Use sortto achieve the sort. If you need something like sql statement the same sort on multiple fields, multiple elements can be passed in the sort inside.

   
   
POST /movies/_search
{
"sort": [{ "year": { "order": "desc"}},
{ "id.keyword": { "order": "desc"}} ],
"from": 0,
"size": 20,
"query": {
"match_all": {}
}
}
  
  

3 _source filter

 Too many results Elasticsearch query, it will affect the efficiency of execution. Therefore, we can reduce query fields by filtration _source way.

  The following query to display only the title attribute

   
   
POST /movies/_search
{
"sort": [{ "year": { "order": "desc"}},
{ "id.keyword": { "order": "desc"}} ],
"from": 0,
"size": 20,
"_source": [ "title"],
"query": {
"match_all": {}
}
}
  
  

4 Script field

  Elasticsearch also supports painless script field, this mechanism can do some simple operations by way of the script, such as: string concatenation. In order scenario, orders have different exchange rates, calculated by the script, we can sort the results for the calculation.

  

   
   
POST /movies/_search
{
"sort": [{ "year": { "order": "desc"}},
{ "id.keyword": { "order": "desc"}} ],
"from": 0,
"size": 20,
"query": {
"match_all": {}
}
, "script_fields": {
"new_title": {
"script": {
"lang": "painless",
"source": "doc['year'].value+'hello'"
}
}
}
}
  
  

5 match expression statement

 1) query match, the contents of the query is OR default way. As follows:

   
   
POST /movies/_search
{
"query": {
"match": {
"title": "last christmas"
}
}
}
  
  

 2) If you are using AND manner, may be achieved by specifying the operator is and.

   
   
POST /movies/_search
{
"query": {
"match": {
"title": {
"query": "last christmas",
"operator": "and"
}

}
}
  
  

6 phrase queries 

   Use the phrase queries. Namely:phrase query . No gaps among phrases default, but may be used to represent intermediate slop = 1 may be spaced a Term (word)

   
   
POST /movies/_search
{
"query": {
"match_phrase": {
"title":{
"query": "one love",
"slop": 1
}
}
}
}
  
  

二 Query string && Simple query string

    1 Elasticsearch also supports query string and simple query string. Let's look query string, in this way supports packet and multi-field.

 First, two test data insert

   
   
PUT /users/_doc/ 1
{
"name": "Ruan Yiming",
"about": "java, golang, node, swift, elasticsearch"
}

PUT /users/_doc/ 2
{
"name": "Li Yiming",
"about": "Hadoop"
}
  
  

test:

   
   
POST /users/_search
{
"query": {
"query_string": {
"default_field": "name",
"query": "Ruan AND Yiming"
}
}
}

# 多字段 使用 fields
POST /users/_search
{
"query": {
"query_string": {
"fields": [ "name", "about"],
"query": "(Ruan AND Yiming) OR (Java AND Elasticsearch)"
}
}
}

  
  

simple query string, similar to the query string, but with the following differences:

1. Grammar errors are ignored, and only supports parts of the query syntax
2. Does not support AND, , OR, NOTif the term appears, will be treated as a string
3. term relationship between the default OR, you can specify default_operator
4. Support part of the logic, +instead of AND, |instead of OR, -instead ofNOT

   
   
POST users/_search
{
"query": {
"simple_query_string": {
"query": "Zhang Fubing",
"fields": [ "name"],
"default_operator": "AND"
}
}
}