SQLite cursor return empty cursor while using where

Question

With following code

resultSet = mydatabase.rawQuery("Select * from devicelog  ", null);
        Log.e("SyncService", "query fiered..");
        if (resultSet.moveToFirst()) {
            Log.e("SyncService", "moved to first..");
            do {
                Log.e("DB_R", "id: " + resultSet.getInt(resultSet.getColumnIndex("id")));
                Log.e("DB_R", "type: " + resultSet.getString(resultSet.getColumnIndex("type")));
                Log.e("DB_R", "action: " + resultSet.getString(resultSet.getColumnIndex("action")));
                Log.e("DB_R", "oldvalue: " + resultSet.getString(resultSet.getColumnIndex("oldvalue")));
                Log.e("DB_R", "newvalue: " + resultSet.getString(resultSet.getColumnIndex("newvalue")));
                Log.e("DB_R", "devicedt: " + resultSet.getString(resultSet.getColumnIndex("devicedt")));
                Log.e("DB_R", "batterysts: " + resultSet.getDouble(resultSet.getColumnIndex("batterysts")));
                Log.e("DB_R", "syncdt: " + resultSet.getString(resultSet.getColumnIndex("syncdt")));
                Log.e("DB_R", "deviceid: " + resultSet.getString(resultSet.getColumnIndex("deviceid")));
            } while (resultSet.moveToNext());
        }
        if (resultSet != null && !resultSet.isClosed()) {
            resultSet.close();
        }

        if (mydatabase != null && mydatabase.isOpen()) {
            mydatabase.close();
        }
        Log.e("SyncService", "query closed..");

I am getting following output in adb logcat

10-15 19:46:33.233: E/SyncService(2446): b4 try..
10-15 19:46:33.294: E/SyncService(2446): query fiered..
10-15 19:46:33.294: E/SyncService(2446): moved to first..
10-15 19:46:33.324: E/DB_R(2446): id: 1
10-15 19:46:33.324: E/DB_R(2446): type: SETTINGS
10-15 19:46:33.324: E/DB_R(2446): action: IP changed
10-15 19:46:33.333: E/DB_R(2446): oldvalue: 0.0.0.0:0
10-15 19:46:33.333: E/DB_R(2446): newvalue: 10.20.30.40:50
10-15 19:46:33.333: E/DB_R(2446): devicedt: 2014-10-15 11:01:40
10-15 19:46:33.355: E/DB_R(2446): batterysts: 0.5
10-15 19:46:33.355: E/DB_R(2446): syncdt: null
10-15 19:46:33.355: E/DB_R(2446): deviceid: e4:2d:02:0f:8f:4a
10-15 19:46:33.355: E/SyncService(2446): query closed..

So one record exist with syncdt = null. But when I fire following query with same code

resultSet = mydatabase.rawQuery("Select * from devicelog where syncdt = null ", null);

I am getting empty cursor as follows:

10-15 19:50:49.957: E/SyncService(2530): b4 try..
10-15 19:50:50.117: E/SyncService(2530): query fiered..
10-15 19:50:50.157: E/SyncService(2530): query closed..

Am I using wrong way to check for null values?

maybe syncdt is not "null" as string but empty?

A.S.
– A.S.

2014-10-15 14:36:42 +00:00
Commented Oct 15, 2014 at 14:36 — A.S.
– A.S., Commented Oct 15, 2014 at 14:36

Giru Bhai · Accepted Answer · 2014-10-15 14:37:41Z

1

To get null values in where use is null,So change your query from

resultSet = mydatabase.rawQuery("Select * from devicelog where syncdt = null ", null);

to

resultSet = mydatabase.rawQuery("Select * from devicelog where syncdt is null", null);

answered Oct 15, 2014 at 14:37

Giru Bhai

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1 Comment

Giru Bhai Over a year ago

@Ankit Happy to help,enjoy.

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