Question

我有多个相同的日期，我想对日期进行分组，因此我有一个time和bg_reading数组，因为同一日期会有多个值。这就是我的JSON吐出来的。

`[
  {
    "date": "2016-03-18T00:00:00.000Z",
    "time": "22:03:54",
    "bg_reading": 9.4
  },
  {
    "date": "2016-03-19T00:00:00.000Z",
    "time": "12:05:56",
    "bg_reading": 12.4
  },
  {
    "date": "2016-03-20T00:00:00.000Z",
    "time": "01:17:06",
    "bg_reading": 15.5
  },
  {
    "date": "2016-03-21T00:00:00.000Z",
    "time": "06:27:42",
    "bg_reading": 17.1
  },
  {
    "date": "2016-03-22T00:00:00.000Z",
    "time": "06:19:21",
    "bg_reading": 27.6
  },
  {
    "date": "2016-03-22T00:00:00.000Z",
    "time": "17:03:27",
    "bg_reading": 14.5
  },
  {
    "date": "2016-03-18T00:00:00.000Z",
    "time": "22:03:54",
    "bg_reading": 9.4
  },
  {
    "date": "2016-03-19T00:00:00.000Z",
    "time": "12:05:56",
    "bg_reading": 12.4
  },
  {
    "date": "2016-03-20T00:00:00.000Z",
    "time": "01:17:06",
    "bg_reading": 15.5
  },
  {
    "date": "2016-03-21T00:00:00.000Z",
    "time": "06:27:42",
    "bg_reading": 17.1
  },
  {
    "date": "2016-03-22T00:00:00.000Z",
    "time": "06:19:21",
    "bg_reading": 27.6
  },
  {
    "date": "2016-03-22T00:00:00.000Z",
    "time": "17:03:27",
    "bg_reading": 14.5
  },
  {
    "date": "2016-03-18T00:00:00.000Z",
    "time": "22:03:54",
    "bg_reading": 9.4
  },
  {
    "date": "2016-03-19T00:00:00.000Z",
    "time": "12:05:56",
    "bg_reading": 12.4
  },
  {
    "date": "2016-03-20T00:00:00.000Z",
    "time": "01:17:06",
    "bg_reading": 15.5
  },
  {
    "date": "2016-03-21T00:00:00.000Z",
    "time": "06:27:42",
    "bg_reading": 17.1
  },
  {
    "date": "2016-03-22T00:00:00.000Z",
    "time": "06:19:21",
    "bg_reading": 27.6
  },
  {enter code here
    "date": "2016-03-22T00:00:00.000Z",
    "time": "17:03:27",
    "bg_reading": 14.5
  }
]`

我希望能有这样的东西：

`[
  {
    "date": "2016-03-18T00:00:00.000Z",
    "time": ["05:22:33", "09:33:10", "15:01:34", "18:03:34", "21:34:09"],
    "bg_reading": [9.4, 6.3, 13.3, 6.8, 7.3]
  }...
]`

但是现在我不知道为什么有这么多的重复值以及为什么有多个日期。这就是我试图在Sequelise上查询它的方式。

`  Log.findAll({
    where: {
      bg_reading: {gt: 0}
    },
    attributes: ['date', 'time', 'bg_reading'],
    group: 'date',
  })
  .then(function(data) {
    res.send(data)
  })
`

Answer 1

首先 - 您在同一日期获得多个条目确实很奇怪。我的猜测是，日期实际上在一天中的时间有所不同，即使它看起来并非如此。尝试提取日期部分。既然你还没有指定SQL方言我会在psql中给出例子，但是你应该能够在mysql等中找到类似的方法。

 group: 'date_trunc('day', date)'

仅按日期部分分组（它将日期时间截断为日期，以便小时，分钟，秒等为0）

为了获得时间和bg_reading的数组，你需要选择它 - 在pg中该函数被称为array_agg（mysql中的group_concat）

attributes: [sequelize.fn('array_agg', sequelize.col('time')) ...],

输出为JSON时，我可以将数据库的列分组到数组中吗？

1 个答案: