我想将我从mysql获得的结果推送到一个空数组(totalJuice)
var sqlgetgauge =
"SELECT juice1_num FROM `customers_out` WHERE MONTH(date)=4 ";
connection.query(sqlgetgauge, function(err, results, field) {
if (err) throw err;
for (i = 0; i < results.length; i++) {
var numberjuice1 = Number(results[i].juice1_num / 100);
var totalJuice = [];
totalJuice.push(numberjuice1);
console.log(totalJuice);
//This is a Gauge Update
juice_num_1.update({
value: numberjuice1,
});
}
});
但是这段代码不断通过console.log(totalJuice)向我显示结果;
gauge_picker.js:85 [0.5]
gauge_picker.js:85 [0.02]
gauge_picker.js:85 [0.02]
我期望数组将是[0.5,0.02,0.02]
还有一个问题是我如何才能得到这个数组的总数?
最佳答案
你的问题是这个声明
var totalJuice = [];
因为它在您的
for
循环内,所以每次都会重置该数组,这意味着您只会获得数组中的最后一个值。您需要将该声明移到for
循环之前,例如var totalJuice = [];
for (i = 0; i < results.length; i++) {
...
要获得所有值的总和,可以在循环后执行
sum = totalJuice.reduce((c, v) => c + v);