#头条创作挑战赛#

职位查询案例

一、查询职位索引库中的一条数据

format：表示指定返回的数据类型

// 1. 查询职位信息
GET /_sql?format=txt
{
    "query": "SELECT * FROM job_idx limit 1"
}

除了 txt 类型，Elasticsearch SQL 还支持以下类型

二、将 SQL 转换为 DSL

GET /_sql/translate
{
    "query": "SELECT * FROM job_idx limit 1"
}

三、职位 scroll 分页查询

1、第一次查询

// 2. scroll分页查询
GET /_sql?format=json
{
    "query": "SELECT * FROM job_idx",
    "fetch_size": 10
}

fetch_size 表示每页显示多少数据，而且当我们指定 format 为 Json 格式时，会返回一个 cursor ID

2、第二次查询

GET /_sql?format=json
{
    "cursor": "5/WuAwFaAXNARFhGMVpYSjVRVzVrUm1WMFkyZ0JBQUFBQUFBQUFJZ1dUM054VUZaMk9YVlJWalowYkVJeFowUkdVak10ZHc9Pf8PCgFmBGFyZWEBBGFyZWEBB2tleXdvcmQBAAABZgNjbXABA2NtcAEHa2V5d29yZAEAAAFmA2VkdQEDZWR1AQdrZXl3b3JkAQAAAWYDZXhwAQNleHABB2tleXdvcmQBAAABZgJpZAECaWQBBGxvbmcAAAABZgJqZAECamQBBHRleHQAAAABZghqb2JfdHlwZQEIam9iX3R5cGUBB2tleXdvcmQBAAABZgJwdgECcHYBB2tleXdvcmQBAAABZgZzYWxhcnkBBnNhbGFyeQEHa2V5d29yZAEAAAFmBXRpdGxlAQV0aXRsZQEEdGV4dAAAAAL/Aw=="
}

3、清除游标

POST /_sql/close
{
    "cursor": "5/WuAwFaAXNARFhGMVpYSjVRVzVrUm1WMFkyZ0JBQUFBQUFBQUFJZ1dUM054VUZaMk9YVlJWalowYkVJeFowUkdVak10ZHc9Pf8PCgFmBGFyZWEBBGFyZWEBB2tleXdvcmQBAAABZgNjbXABA2NtcAEHa2V5d29yZAEAAAFmA2VkdQEDZWR1AQdrZXl3b3JkAQAAAWYDZXhwAQNleHABB2tleXdvcmQBAAABZgJpZAECaWQBBGxvbmcAAAABZgJqZAECamQBBHRleHQAAAABZghqb2JfdHlwZQEIam9iX3R5cGUBB2tleXdvcmQBAAABZgJwdgECcHYBB2tleXdvcmQBAAABZgZzYWxhcnkBBnNhbGFyeQEHa2V5d29yZAEAAAFmBXRpdGxlAQV0aXRsZQEEdGV4dAAAAAL/Aw=="
}

四、职位全文检索

1、需求

检索 title 和 jd 中包含 hadoop 的职位

2、MATCH 函数

在执行全文检索时，需要使用到 MATCH 函数

MATCH(
    field_exp,   
    constant_exp 
    [, options]) 

• field_exp：匹配字段
• constant_exp：匹配常量表达式

3、实现

GET /_sql?format=txt
{
    "query": "select * from job_idx where MATCH(title, 'hadoop') or MATCH(jd, 'hadoop') limit 10"
}