如何在JavaScript中查找表格中特定列的长度? [英] How to find the length of a particular column of a table in javascript?

问题描述

我在项目中使用sqlite数据库.

I am using sqlite database in my project.

我的表结构几乎像这样

id  cid values

1   1   value1
2   1   value2
3   1   value3
4   1   value4
5   2   value1
6   2   value2
7   3   value1
8   3   value2
9   3   value3

所以我想要同一个 cid 的所有值，我应该如何编码?

so I want all the values of the same cid,how should I code it?

我的查询:

tx.executeSql("SELECT cid,value FROM table where cid="+cid_value, [], querySuccess, errorCB,cid_value);

因为，当我按以下方式尝试时，

because,when I tried it the following manner,

var details = results.rows.length;
console.log("db test value:"+results.rows.item(cid_value).value);
for (var i=cid_value; i<details; i++)
{
cidinstance=results.rows.item(i).cid;
var valueinstance=results.rows.item(i).value;
document.getElementById("s"+i+"cause").innerHTML=valueinstance;
console.log("cid= "+cidinstance +   "valueinstance= "+valueinstance);
}

然后，当i = cid_value(cid_value = 1)定位到cid = 1时，我们有四个值，我得到的只是 3个值.但是，如果我输入 i = 0 ，那么我得到 4个值

then when i=cid_value(cid_value=1) targeting cid=1, where we have four values I get just 3 values.but,if i put i=0,then I get 4 values

当 i = cid_value(cid_value = 2)定位到cid = 2时，我得到以下信息

when i=cid_value(cid_value=2) targeting cid=2,i get the following

01-01 05:45:38.687: I/Web Console(2425): JSCallback: Message from Server:  SQLitePluginTransaction.queryCompleteCallback('1104538538488000','1104538538491000', [{"value":"value1","cid":"2"},{"value":"value22","id":"6","cid":"2"}]); at file:///android_asset/www/cordova-2.1.0.js:3726.

问题是，当我从服务器获取消息作为JS回调时，我正在获取值.不是来自for循环

请，建议我解决问题的方法！指导我找到出路.

Please,suggest me ways to solve the problem!.guide me to find a way out.

推荐答案

如果要查找列出特定CID的行数，则需要在SQLite中使用COUNT函数.

If you want to find the number of rows where a particular CID is listed, you need to use the COUNT function in SQLite.

所以您的陈述将为::

So your statement would be ::

SELECT COUNT(values) FROM TableName WHERE cid=1 

那将直接给您计数.您不需要任何代码即可自己进行计算.

That will give you the count directly. You don't need any code to do the calculations yourself.

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