Elastic search Filters

Filter

GET courses/_search
{
  "query" :{
    "bool":{
      "filter" :{
        "match": {"name": "accounting"}
      }
    }
  }
}
Filters does not do relevancy scoring
Primarilary used for fetching the data.
Filters are cached.

Mix of Filter and query

GET courses/_search
{
  "query" :{
    "bool":{
      "filter" :{
        "bool":{
          "must":[
            {"match": {"name": "accounting"}}
            
            ]
           
        }
      },
       "must": [
              {"match": {"room":"e3"}}
              ]
    }
  }
}

Use of "MUst" in filters

GET courses/_search
{
  "query" :{
    "bool":{
      "filter" :{
        "bool":{
          "must":[
            {"match": {"name": "accounting"}},
            {"match": {"professor.name": "bill"}}
            ]
        }
      }
    }
  }
}

Use of Must in filter

GET courses/_search
{
  "query" :{
    "bool":{
      "filter" :{
        "bool":{
          "must":[
            {"match": {"name": "accounting"}},
            {"match": {"professor.name": "bill"}}
            ],
            "must_not": [
              {"match": {"room":"e7"}}
              ]
        }
      }
    }
  }
}

use of should with filter

GET courses/_search
{
  "query" :{
    "bool":{
      "filter" :{
        "bool":{
          "must":[
            {"match": {"name": "accounting"}}
            
            ]
           
        }
      },
       "should": [
              {"match": {"room":"e3"}}
              ]
    }
  }
}