如何在弹性搜索中参数为空或空时忽略查询约束

Question

Elastic Noob here, I have the following query for the elastic search index. in which I try to filter the records based on the title of the product record.

"query" => [
    "bool" => [
        "should" => [
            [
                "nested" => [
                    "path"  => "name",
                    "query" => [
                        "multi_match" => [
                            "query"  => (string) $query, // here the $query can be empty string
                            "fields" => ['name.en', 'name.ar'],
                        ],
                    ],
                ],
            ],
        ],
    ],
];

Now the parameter $query (please see the commented section in the sample code) can be an empty string. In that case, now I am getting zero results, Obviously because I don't have any records with an empty title.

What I would like to get

is to essentially ignore the query since the parameter is empty and to get a default result set back.

I have more queries like category, tags, reviews etc... so even when the name/title query is empty, I should be able to filter based on the other queries. But now if the name part is empty I am getting an empty result set.

Please post a comment if more info is needed

Elasticsearch 7

Answer 1

是的，有Elasticsearch解决方案： 零项查询 。

Answer 2

In a match or multi_match query an empty string will be ingored if one uses zero_terms_query option, like this:

{
  "query": {
    "bool": {
      "must": [
        {
          "multi_match": {
            "query": "",
            "zero_terms_query": "all",
            "fields": ["name.en", "name.ar"]
          }
        }
      ]
    }
  }
}

or match version:

{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "name": {
              "query": "",
              "zero_terms_query": "all"
            }
          }
        }
      ]
    }
  }
}

See zero terms query

Answer 3

Try to change the name.en and name.ar to keyword type. In ES, only keyword type field is valid for empty string.