Question

我在PostgreSQL中有以下查询：

select bookings."memberId" from bookings
join "memberConnections" mbc on bookings."memberId" = mbc."memberId"
join shifts shf on shf.id = bookings."shiftId"
where bookings.state = 'WAITING_LIST' and (mbc.state = 'LOCKED' or mbc.state = 'REMOVED')
and shf."startTime" > CURRENT_TIMESTAMP;

我正在将其导入文件中，然后通过名为的库处理数据 Knex.js

当我运行它并控制台记录查询时，我得到以下结构：

USER_STATE: Result {
  command: 'SELECT',
  rowCount: 32,
  oid: NaN,
  rows: 
   [ anonymous { memberId: 1800 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 19668 },
     anonymous { memberId: 19668 },
     anonymous { memberId: 21004 },
     anonymous { memberId: 21004 },
     anonymous { memberId: 21004 },
     anonymous { memberId: 21004 },
     anonymous { memberId: 16105 },
     anonymous { memberId: 14927 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 17923 },
     anonymous { memberId: 17273 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 12553 },
     anonymous { memberId: 19429 },
     anonymous { memberId: 17312 },
     anonymous { memberId: 17273 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 15476 },
     anonymous { memberId: 19634 } ],
  fields: 
   [ Field {
       name: 'memberId',
       tableID: 22531,
       columnID: 3,
       dataTypeID: 23,
       dataTypeSize: 4,
       dataTypeModifier: -1,
       format: 'text' } ],
  _parsers: [ [Function: parseInteger] ],
  RowCtor: [Function: anonymous],
  rowAsArray: false,
  _getTypeParser: [Function: bound ] }

这几乎是我所需要的，但是，我只需要memberId数据，有什么方法可以通过它映射以仅获取memberId属性？

我已经尝试过了，但是似乎不起作用：

  const users = userState.map(users => ({
      memberId: memberId;
  }))

Answer 1

您首先需要将该结构转换为 valid JSON 。然后，您可以根据需要在userState.rows上进行处理。

Here 是将 knex.js 响应转换为JSON的参考。
这是使用有效JSON的有效示例-

var userState = {
    rows:
        [{ memberId: 1800 },
        { memberId: 15476 },
        { memberId: 15476 },
        { memberId: 12553 },
        { memberId: 12553 },
        { memberId: 19668 },
        { memberId: 19668 },
        { memberId: 21004 },
        { memberId: 21004 },
        { memberId: 19634 }],
    fields:
        [{
            name: 'memberId',
            tableID: 22531,
            columnID: 3,
            dataTypeID: 23,
            dataTypeSize: 4,
            dataTypeModifier: -1,
            format: 'text'
        }]
};

var data = userState.rows.map((users, index) =>
    users.memberId
);

console.log(data);

Answer 2

尝试一下

const userState = {
    rows: [
        { memberId: 1 },
        { memberId: 2 }
    ]
}

const users = userState.rows.map(users =>
    users.memberId
)

console.log(users)

// [ 1, 2 ]

Answer 3

我认为这会对您有所帮助：https://knexjs.org/#Interfaces-map

我认为是错误的

.map(users => ({
      memberId: memberId;
  }))

应该是：

.map(function(row) {
  return row.memberId;
})

您可以尝试我的解决方案，它可能会起作用，因为我没有将Knex.js与Node.JS一起用于SQL，我通常Sequelize

遍历此结构？

3 个答案: