Getting data according to last hours from sqlite

问题

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

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

Query:

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

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

Eg: there are following record in database

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

which I do not want.

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

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?

Any Help will be appreciated.

回答1:

Use this query for question 1 -

`select * from Table1 where(Date between '(Select Date from Table1 order by Date asc limit 1)' and 'date1');`

date1 should be in formate yyyy-MM-dd hh:mm:ss(for example 2015-10-21 08:00:00). In date1 you can put before 1 hour datetime.

it is working in SQLite Manager.

For question 2 - you have to get data for every hour separately using below query

select * from Table1 where(Date between 'date1' and 'date2');

回答2:

Finally I found the solution to my own question

Following is the code which worked for me

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;

    }

 }

I hope it will help someone in future

来源：https://stackoverflow.com/questions/33254848/getting-data-according-to-last-hours-from-sqlite

标签

sqlite

android-sqlite