Question

我在用sqlite提取总和时遇到了麻烦，它在我的javascript代码中返回了未定义的内容。你能帮我么？这是我的密码。

这是我的index.js代码

    function displayExpenses(results) {
        var length = results.rows.length;
        for(i = 0; i < length; i++) {
            var item = results.rows.item(i);
            var parsedMon = parseInt(item.mon_value);
            var moneyVal = (parsedMon).toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
            console.log(moneyVal);
        }
    }
`````
here is my sqlite code
```
fetchExpenses: function(displayExpenses) {
        databaseHandler.db.readTransaction(
            function(tx) {
                tx.executeSql(
                    "SELECT SUM (mon_value) FROM money WHERE mon_type = '-'",
                    [],
                    function(tx, results) {
                        displayExpenses(results);
                    }
                );
            }
        );
    }

  [1]: https://i.stack.imgur.com/C1b19.png
  [2]: https://i.stack.imgur.com/UgI6F.png
  [3]: https://i.stack.imgur.com/82UN5.png

Answer 1

item.mon_value可能无法工作，除非您给它这样的别名：

rn = range(0,10**18)
it = iter(rn) # could be created from other source, used as example
ls = list(range(0,15))

print(rn)
print(ls)
print(it)

> range(0, 1000000000000000000)
> [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]
> <range_iterator object at 0x7f20cd3866f0>

#I will put some breaks so when you try it, it will stop some day haha

for i in it:
  if(i<20):
    print(i)
  else:
    break

for i in rn:
  if(i<20):
    print(i)
  else:
    break

您可能还需要查看以下内容：How can I assign a name to the SUM column?

在sqlite中获取总和，并在javascript中返回未定义

1 个答案: