Member Avatar for Saboor880

I am making an adroid application. I am saving sales data on firebase with current date. I have formatted the System.currentTimeMillis() into SimpleDateFormat. The date is successfully stored on firebase . Now I want to retrieve sales between two dates. I made two demo sales, one on (30-5-2019) and second on (31-5-2019).
For retrieving the sales data I have just put two above mentioned static dates in my Query and ran it . The problem is that it only gives me one sale record between two dates. It should give me 2 sale records.

Below is my source code.

// Firebase Query
Query Qdates = sales_ref.orderByChild("date").startAt("30-5-2019").endAt("31-5-2019");
        Qdates.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot ssn : dataSnapshot.getChildren()) {

                     Sale sale = ssn.getValue(Sale.class);
                     String id =sale.getId();
                     Toast.makeText(getActivity(),id,Toast.LENGTH_LONG).show();
                     String customerName = sale.getShippingInfo().getFirstname()+""+sale.getShippingInfo().getLastnme();
                     String countryName = sale.getShippingInfo().getCountry();
                     int itemscount = sale.getList().size();

                     SalesListItem salesListItem = new SalesListItem(id,customerName,countryName,itemscount);
                     alSalesListItem.add(salesListItem);
                     }
                final CustomAdapter customadapter = new CustomAdapter();
                lv.setAdapter(customadapter);
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        }) ;

The output should be 2 sales i-e with following IDs;
Lg6SwzRLbYg4fMDs4H6 (this sales is made on 30-5-2019)
Lg8N1n40zMBVq6V_1hL (this sales is made on 31-5-2019)

But I am getting only one sale that is (this sales is made on 30-5-2019)

Why I am not getting both sales? Please see the attached image.

firebase.PNG

  • 4 Contributors
  • 4 Replies
  • 6K Views
  • 1 Year Discussion Span
  • Latest Post Latest Post by Lye

Dani AI

Generated

The behavior you are seeing is typical when dates are stored as strings. Realtime Database orders strings lexicographically, and your endAt("31-5-2019") will exclude values like 31-5-2019 11:00 because they sort after 31-5-2019. Also, string formats without zero-padding do not sort reliably across months and days. The most robust fix is to store a numeric timestamp and query by a millisecond range. Use SimpleDateFormat only for display.

Example approach:

  • Write a dateMillis property as a long (preferably using the server clock to avoid client skew).
  • Compute an inclusive range for the day(s) you want: startOfDay <= dateMillis <= endOfDay.
// When writing
Map<String, Object> sale = new HashMap<>();
sale.put("dateMillis", ServerValue.TIMESTAMP); // resolves to long on the server
sales_ref.push().setValue(sale);

// When querying
Calendar cal = Calendar.getInstance(); // or setTimeZone as needed
cal.set(2019, Calendar.MAY, 30, 0, 0, 0); cal.set(Calendar.MILLISECOND, 0);
long start = cal.getTimeInMillis();
cal.add(Calendar.DATE, 2); // up to end of 31st
long end = cal.getTimeInMillis() - 1;

Query q = sales_ref.orderByChild("dateMillis").startAt(start).endAt(end);

Make sure all records have the same type for the indexed field and add an index for performance:

"rules": { "sales": { ".indexOn": ["dateMillis"] } }

See Filtering data and Server timestamps in the Firebase docs.

Recommended Answers

All 4 Replies

Member Avatar for JamesCherrill

I don't know firebase, but as nobobdy else has answered....

MAYBE there's a time attached to that data, eg
30-5-2019 10am
31-5-2019 11am
and your query is defaulting to midnight, ie 30-5-2019 00:00 to 31-5-2019 00:00
???

If so the fix is to end the date range with a date one day later.

commented: The more I thought about your reply the more likely that's it. +15
commented: Thanks for trying James. Actually there was need to convert the string date in date object, I did so and the problem solved +3
Member Avatar for juan_24

Hai brother can u explain more about this because I also have a implementation by this

Member Avatar for Saboor880

Problem solved. Thanks

Member Avatar for Lye

Can you show me how to solve this question

commented: Look up. " there was need to convert the string date in date object, I did so and the problem solved" -3
commented: why not create a new post instead? +0
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