[elasticsearch] A document doesn't have a value for a field

 在 Elasticsearch 中使用query的時候， 如果指定的欄位不存在的話，會發生 error illegal_state_exception 。
可以按照response內的建議，使用 doc[<field>].size()==0  或是 doc.containsKey('myfield') 去做檢查。

          "caused_by" : {

            "type" : "illegal_state_exception",

            "reason" : "A document doesn't have a value for a field! Use doc[<field>].size()==0 to check if a document is missing a field!"

          }

"type" : "script_exception",

        "reason" : "runtime error",

        "script_stack" : [

          "org.elasticsearch.index.fielddata.ScriptDocValues$Doubles.get(ScriptDocValues.java:246)",

          "org.elasticsearch.index.fielddata.ScriptDocValues$Doubles.getValue(ScriptDocValues.java:240)",

          "return 0.3 * doc['test_field'].value;",

          "                          ^---- HERE"

        ],

Using Datetime in Painless | Painless Scripting Language [8.3] | Elastic https://www.elastic.co/guide/en/elasticsearch/painless/8.3/painless-datetime.html

"When a query’s results span multiple indexes, some indexes may not contain a specific field. Use the containsKey method call on the doc input to ensure a field exists as part of the index for the current document."