ES笔记

ES牛逼的学习资料：https://pdai.tech/md/db/nosql-es/elasticsearch-x-dsl-com.html

参考：https://www.jianshu.com/p/b2c0192e6267

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举例：初始化数据

PUT mmm/_doc/1
{
  "name": "北京",
  "ct": "2022-08-01"
}

PUT mmm/_doc/2
{
  "name": "上海",
  "ct": "2022-08-10"
}

PUT mmm/_doc/3
{
  "name": "广州",
  "ct": "2022-08-20"
}

must和should同时存在同一层时，由于should只为打分使用，minimum_should_match默认是0，所以实际上should是不生效的，有两种解决办法，

1. 同一层加上minimum_should_match = 1，如

GET /mmm/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "range": {
            "ct": {
              "gte": "2022-08-09"
            }
          }
        }
      ],
      "should": [
        {
          "term": {
            "name.keyword": {
              "value": "北京"
            }
          }
        },
        {
          "term": {
            "name.keyword": {
              "value": "上海"
            }
          }
        }
      ],
      "minimum_should_match": 1
    }
  }
}

2. 将should外面再套一层bool，如：

GET /mmm/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "range": {
            "ct": {
              "gte": "2022-08-09"
            }
          }
        },
        {
          "bool": {
            "should": [
              {
                "term": {
                  "name.keyword": {
                    "value": "北京"
                  }
                }
              },
              {
                "term": {
                  "name.keyword": {
                    "value": "上海"
                  }
                }
              }
            ]
          }
        }
      ]
    }
  }
}

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term, terms查询
term：select * from xxx where id = ?
terms: select * from xxx where id = ? or id = ? or id = ?，也相当于select * from xxx where id in (?, ?, ?)

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聚合：参考：https://pdai.tech/md/db/nosql-es/elasticsearch-x-agg-bucket.html