面试题：ElasticSearch脚本字段的复杂逻辑实现

Question

假设文档中有一个日期字段'timestamp'，现在要通过脚本字段根据'timestamp'计算文档距离当前时间的天数差，且仅在满足某个特定条件（如另一个字段'category'为'important'）时才计算，写出完整的ElasticSearch查询语句及脚本实现。

Answer 1

{
    "query": {
        "bool": {
            "filter": [
                {
                    "term": {
                        "category": "important"
                    }
                }
            ]
        }
    },
    "script_fields": {
        "days_since_timestamp": {
            "script": {
                "source": "def now = new Date(); def timestampDate = new Date(doc['timestamp'].value); return (now.getTime() - timestampDate.getTime()) / (24 * 60 * 60 * 1000);"
            }
        }
    }
}