select 值 json 到其他 json (Postgres)

Question

我有以下 JSON

{
  "eventSummaryList": [
    {
      "customer": "189256",
      "data": "{\"cliente\":\"189256\",\"data_posicao\":\"1491426372\",\"gps_valido\":\"1\",\"horimetro\":\"120561\",\"ibuttonHex\":\"0\",\"ibuttonPart1\":\"0\",\"ibuttonPart2\":\"0\",\"id_evento\":\"null\",\"id_motorista\":\"0\",\"ignicao\":\"1\",\"latitude\":\"-2222222\",\"longitude\":\"-2222222\",\"odometro\":\"253692\",\"pos_memoria\":\"0\",\"veiculo\":\"44444\",\"velocidade\":\"50\"}",
      "identifierEventRule": "77404",
      "identifierRule": "6",
      "identifierSummary": "28901976",
      "rule": "velocidade_maior_que",
      "status": 1,
      "vehicle": "44444"
    }
  ],
  "header": {
    "mensagem": {
      "estilo": "SUCCESS",
      "mensagem": "Successfully executed service",
      "plataforma": "EVENT_POINT",
      "status": "SUCESSO"
    }
  }
}

我需要提取值 "velocidade" 里面有什么 "data" 包含另一个 json.

我正在使用以下语法，但它 returns 为空。

select  cast((value::json ->'data')::json->> 'velocidade' AS   int)    AS velocidade,

Answer 1

尝试：

SELECT ((value::json #>> '{eventSummaryList,0,data}')::json ->> 'velocidade')::int

（#>> 或 ->> 运算符是关键。如果您使用 #> 或 ->，您将得到 json -encoded json 字符串。顺便说一句，这真的是一个混乱的模型，我会考虑修复它的输入 first/instead。）

http://rextester.com/THVYFK9026

select 值 json 到其他 json (Postgres)

select values in json into other json (Postgres)

postgresql

json

pipelinedb