如何将 Javascript 调用中的 SQL 字段名称返回给 API？

Question

我为本地 mysql 数据库与 Express、Cors 和 Node 组合了一个 API，现在我正在尝试提取数据。 我有一个查询，我在其中构建了一个旨在提取一系列统计信息的 const，但我不知道如何最好地提取数据，以便 json 中的每个元素都有正确的字段：

const express = require('express');
const cors = require('cors');
const mysql = require('mysql');

const app = express();

const COUNTS_QUERY = 'SELECT COUNT(*) AS total_stands FROM carts UNION SELECT SUM(current_orders) as total_orders FROM carts UNION SELECT AVG(rating) as rating FROM carts';

app.listen(4000, () => {
    console.log('Server listening on port 4000')
});

//call query to count trucks
app.get('/stats', (req, res) => {
    connection.query(COUNTS_QUERY, (err, results) => {
        if(err) {
            return res.send(err)
        } else {
            console.log(results)
            return res.json({
                data: results
            })
        }
    })
})

我收到以下结果：

{"data":[{"total_stands":1541},{"total_stands":35218},{"total_stands":2.9792}]}

如何取回 object，其中每个统计数据都有适当的字段名称？

Answer 1

使用此查询以接收此 output： {"data":[{"total_stands":1541},{"total_orders":35218},{"rating":2.9792}]}

SELECT
    (SELECT COUNT(*) AS total_stands FROM carts) AS  total_stands,
    (SELECT SUM(current_orders) as total_orders FROM carts) AS total_orders,
    (SELECT AVG(rating) as rating FROM carts) AS rating