腳本場數數組長度

Question

我有以下文件：

{ 
    "likes": { 
    "data": [ 
     { 
     "name": "a" 
     }, 
     { 
     "name": "b" 
     }, 
     { 
     "name": "c" 
     } 
    ] 
    } 
} 

我試圖運行update_by_query，將增加一個名爲「LIKE_COUNT」字段的數組項數內likes.data

重要的是要知道，並非我的所有文檔都有likes.data對象。

我試圖這樣：

POST /facebook/post/_update_by_query 
{ 
    "script": { 
    "inline": "if (ctx._source.likes != '') { ctx._source.like_count = ctx._source.likes.data.length }", 
    "lang": "painless" 
    } 
} 

但是，讓此錯誤消息：

{ 
    "type": "script_exception", 
    "reason": "runtime error", 
    "script_stack": [ 
     "ctx._source.like_count = ctx._source.likes.data.length }", 
     "            ^---- HERE" 
    ], 
    "script": "if (ctx._source.likes != '') { ctx._source.like_count = ctx._source.likes.data.length }", 
    "lang": "painless" 
    } 

Answer 1

嘗試ctx._source['likes.data.name'].length

根據https://www.elastic.co/guide/en/elasticsearch/reference/current/nested.html，在ES對象陣列被變平以

{ 
    "likes.data.name" :["a", "b", "c"] 
} 

我們認爲是嵌套數據類型的對象數組數據類型。