javascript - 对按第二个表键分组的数据库值求和

Question

我有以下表格

条码唯一的账单支付表

barcode    amount    receiptno
123        10        1
124        20        1
125        10        2
126        10        2
127        20        3

带有唯一条码的账单表

barcode    buildingcode  
123        1001
124        1001
125        1002
126        1002
127        1002

我想显示按这样的构建代码分组的金额总和

buildingcode     sum amount
1001             30
1002             40

我使用以下代码，但我只按receiptno 分组

t.executeSql('SELECT barcode, SUM(amount) AS myamount, receiptno FROM billpayments WHERE receiptno > 0 GROUP BY receiptno', 
        [], function(t, resultcollect) {

            len = resultcollect.rows.length;

            function dummy(i){
                var row = resultcollect.rows.item(i);
                t.executeSql('SELECT barcode, buildingcode FROM bill WHERE barcode = ?', 
                    [row.barcode], function(t, collectaddress) {
                        mybill = collectaddress.rows.item(0);

                        if (row.receiptno != 0){
                            items.push('<tr><td>' + row.receiptno + '</td><td>' + mybill.buildingcode + '</td><td><font color="blue">' + row.myamount.toFixed(2) + '</font></td><td></td></tr>');
                        }
                    });
            }

            for (i = 0; i < len; i += 1) {
                dummy(i);
            }

我怎样才能做到这一点？

Answer 1

SELECT buildingcode, SUM(amount)
FROM bill JOIN billpayments ON bill.barcode = billpayments.barcode
GROUP BY buildingcode