Elasticsearch:在文档字段的值中获取子字符串? [英] Elasticsearch: get for a substring in the value of a document field?

问题描述

在 mysql 中，我可以使用 sql SELECT LEFT(field，4)from table 来搜索字段的4个字节.

Elasticsearch 有相似的语法吗?

解决方案

借助ES，您可以使用

然后在您的响应中，您将获得一个名为 left_field 的字段，其中将包含 field 值的最左边四个字符.

还要确保启用动态脚本以使其正常工作.

In mysql I can use the sql SELECT LEFT(field,4) from table to search 4 bytes of a field.

Elasticsearch has similar grammar?

解决方案

With ES, you can use script_fields in order to perform any script computation on existing fields.

In your case, this would translate to making a query like this:

{
    "query" : {
        "match_all": {}
    },
    "script_fields" : {
        "left_field" : {
            "script" : {
                "inline": "doc.field.value.substring(0, length)"
                "params": {
                    "length": 4
                }
            }
        }
    }
}

Then in your response you'll get a field named left_field which will contain the 4 left-most characters of the field value.

Also make sure to enable dynamic scripting in order for this to work.

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