从SQLite获取根据过去小时的数据 [英] Getting data according to last hours from sqlite

问题描述

我想按小时从sqlite数据库中获取记录.以下是我的问题

I want to get records out of sqlite database according to hours. following are my questions

1)我必须在过去一小时内从sqlite提取所有数据.我尝试了以下查询，但它为我提供了当天所有时段的数据

1) I have to extract all data from sqlite for past one hour. I have tried following query but it provide me data for all the hours in present day

查询:

SELECT * FROM Table1 where Date >= datetime('now','-1 hours')

其中Table1是我的表名，而Date是DATETIME类型的列名

Where Table1 is my table name and Date is coloumn name of type DATETIME

例如:数据库中有以下记录

Eg: there are following record in database

当我在sqlite firefox浏览器工具中触发查询时，它会返回我

When I fire query in sqlite firefox browser tool it returns me

我不想要的.

从数据库中获取过去1小时数据的查询应该是什么

What should be the query to get past 1 hour data from database

2)应该查询什么才能根据每小时从数据库中获取值，比如我必须获取过去1个小时的数据，然后获取过去1-2个小时的数据，过去2-3个小时的数据，即两个小时之间有一个小时的数据?

2) What should be query to get the value out of database according to every hours, like I have to get data for past 1 hour, then data of past 1-2 hour, the data of past 2-3 hour i.e an hour data between two hours?

任何帮助将不胜感激.

推荐答案

最后，我找到了解决自己问题的方法

Finally I found the solution to my own question

以下是对我有用的代码

DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = new Date();
        Calendar calendar = Calendar.getInstance();
        String startDate = dateFormat.format(date);
        String endDate = "";
        for (int i = 1; i <= 24; i++) {
            System.out.println("Start Date:- " + startDate);
            calendar.add(Calendar.HOUR_OF_DAY, -1);
            date = calendar.getTime();
            endDate = dateFormat.format(date);
            System.out.println("End Date:- " + endDate);
            String data = dbAdapter.getOutDoorHourlyData(startDate, endDate);
            System.out.println("Hourly Average:- " + data);
            startDate = endDate;
            endDate = "";
        }

public String getOutDoorHourlyData(String startDate, String endDate) {
        double outdoorHourly = 0;

        Cursor cursor = _sqliteDB.rawQuery("Select AVG("
                + COLOUMN_NAME + ") from (Select * FROM "
                + TABLE_NAME + " where " + COLOUMN_NAME + " >= '"
                + endDate + "' and " + COLOUMN_NAME + " < '" + startDate
                + "')", null);

        try {

            if (cursor != null) {
                if (cursor.getCount() > 0) {
                    cursor.moveToFirst();
                    do {
                        outdoorHourly = cursor.getDouble(0);
                    } while (cursor.moveToNext());
                }
                cursor.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        String hourlyData = decimalFormat.format(outdoorHourly);
        hourlyData = hourlyData.replace(",", ".");
        return hourlyData;

    }

 }

我希望它将来能对某人有所帮助

I hope it will help someone in future

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