Develop Reference

Android: Get entire column data

Im trying to get the data of an entire column into a string array. My database contains two columns Id and Names. I want to read all the entries of the names column and put it into a array. Please help.
EDIT #1:
Im using the following code but i can get only one name with this code.
String query = "Select * FROM " + TABLE_APPS + " WHERE " + COLUMN_NAME + " = \"" + productname + "\"";
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);
if (cursor.moveToFirst()) {
cursor.moveToFirst();
name = cursor.getString(1);
cursor.close();
} else {
name = null;
}
db.close();

int total=0;
Cursor csr=sdb.query("tablename", null, null,null,null,null,null);
csr.moveToFirst();
while(!csr.isAfterLast())
{
total++;
csr.moveToNext();
}
String strarray[] = new String[total];
Cursor csrs=sdb.query("tablename", null, null,null,null,null,null);
csrs.moveToFirst();
int aray=0;
while(!csrs.isAfterLast())
{
strarray[aray]=csrs.getString(1);
aray++;
csrs.moveToNext();
}

Get data from database Android

I have a page which can retrieve user data from database
but after whole day of trying, I am only able to get the table column name but not the value inside.
this is my code to create database
public static final String LASTLOGIN = "lastuser";
public static final String USER_ID = "suser_id";
public static final String USER_NAME = "suser_name";
public static final String USER_PASSWORD = "spassword";
public static final String PRIME_ID = "id";
private static final String TABLE_USER =
"create table "+ LASTLOGIN+" ("
+PRIME_ID+" integer primary key autoincrement, "
+ USER_ID + " text, "
+ USER_NAME +" text, "
+USER_PASSWORD+" text); ";
and here is the function implemented to get user data
public Cursor getuser()
{
String[] columns = new String[]{PRIME_ID, USER_NAME, USER_PASSWORD};
Cursor cursor = sqLiteDatabase.query(
LASTLOGIN, columns, null, null, null, null, PRIME_ID +" DESC");
Log.d("TAG", columns[1]);
return cursor;
}
and here is my code to display the result
mySQLiteAdapter = new SQLiteAdapter(this);
mySQLiteAdapter.openToWrite();
cursor = mySQLiteAdapter.getuser();
String[] resultvalue = new String{
SQLiteAdapter.PRIME_ID,SQLiteAdapter.USER_NAME, SQLiteAdapter.USER_PASSWORD};
Toast.makeText(this, resultvalue[0]+resultvalue[1], Toast.LENGTH_LONG).show();
and the toast result only show the column name but not the value inside, is there any mistake i made? and I want to set limit to 1, but where to set it?
Thanks for helping me

the way you try reading the values is completly wrong.
you create an array
String[] resultvalue = new String[]{
SQLiteAdapter.PRIME_ID,
SQLiteAdapter.USER_NAME,
SQLiteAdapter.USER_PASSWORD};
after that you read the values 0 and 1 from this array.
Your toast works absolutly correctly becouse inside this array you define the column names!
If you want to show the values from your query do it this way:
while(cursor.moveToNext()){
Integer str1 = str 1 + cursor.getInteger(1);
String str2 =str2 + cursor.getString(2);
Toast.makeText(this, str1 + str2, Toast.LENGTH_LONG).show();
}
or a better way receiving the correct index:
cursor.getInteger( cursor.getColumnIndex(SQLiteAdapter.PRIME_ID) );
cursor.getString( cursor.getColumnIndex(SQLiteAdapter.USER_NAME) );

Please note when retrieving data from a database, you store it in a Cursor in the memory and hence can only access it using that particular Cursor object, which you have used in the following line of code.
Cursor cursor = mySQLiteAdapter.getuser();
The Following line retrieves the column names and not the values.
String[] resultvalue = new String[]{SQLiteAdapter.PRIME_ID,SQLiteAdapter.USER_NAME, SQLiteAdapter.USER_PASSWORD};
So the following is doing what you have asked it to do, retrieve column names not values
Toast.makeText(this, resultvalue[0]+resultvalue[1], Toast.LENGTH_LONG).show();
You need something like following:
if(cursor.getCount() != 0)
{
while(cursor.moveToNext())
{
resultvalue [0] = csr.getString(0);
resultvalue [1] = csr.getString(1);
//....
}
}
Hope this helps

here is my solution:
final String TABLE_NAME = "table_name";
String selectQuery = "SELECT Column FROM "+TABLE_NAME+" WHERE column='"+some_value+"'";
SQLiteDatabase db = this.openDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
String[] data = new String[cursor.getCount()];;
int i = 0;
if (cursor.moveToFirst()) {
do {
i=Integer.parseInt(cursor.getString(cursor.getColumnIndex("value")));
} while (cursor.moveToNext());
}
cursor.close();

Selecting NULL values in Android SQLite

I'm executing the following method with no success beacause of the selectArgs being incorrect (at least this is what I believe.
findAll:
public Collection<Object> findAllByCodigoSetorOrderByStatusWhereDataAgendamentoIsNull(Integer vendedor) {
Collection<Object> objects = null;
String selection = Object.FIELDS[20] + "=?" + " OR " + Object.FIELDS[20] + "=?" + " OR " + Object.FIELDS[20] + "=?" + " AND " + Object.FIELDS[6] + "=?";
String[] selectionArgs = new String[] { "''", "'null'", "NULL", String.valueOf(vendedor) };
Collection<ContentValues> results = findAllObjects(Object.TABLE_NAME, selection, selectionArgs, Object.FIELDS, null, null, Object.FIELDS[4]);
objects = new ArrayList<Object>();
for (ContentValues result : results) {
objects.add(new Object(result));
}
return objects;
}
findAllObjects:
protected Collection<ContentValues> findAllObjects(String table, String selection, String[] selectionArgs, String[] columns, String groupBy, String having, String orderBy) {
Cursor cursor = null;
ContentValues contentValue = null;
Collection<ContentValues> contentValues = null;
try {
db = openRead(this.helper);
if (db != null) {
cursor = db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);
contentValues = new ArrayList<ContentValues>();
for (int i = 0; i < cursor.getCount(); i++) {
cursor.moveToPosition(i);
contentValue = new ContentValues();
for (int c = 0; c < cursor.getColumnCount(); c++) {
contentValue.put(cursor.getColumnName(c), cursor.getString(c));
}
contentValues.add(contentValue);
cursor.moveToNext();
}
}
return contentValues;
} finally {
close(db);
}
}
How can I correctly select and compare a column to - null, 'null' and '' using the db.query?

Android's database API does not allow to pass NULL values as parameters; it allows only strings.
(This is a horrible design bug. Even worse, SQLiteStatement does allow all types for parameters, but works only for queries that return a single value.)
You have no choice but to change the query string to blah IS NULL.

Old question but i was still stuck on this for a few hours until i found this answer. For whatever reason this strange behaviour (or bug) still exists within the android sdk, if you want to query against null values simply do
SQLiteDatabase db = getReadableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("columnName", newValue);
String nullSelection = "columnName" + " IS NULL";
db.update("tableName", contentValues, nullSelection, null);
db.close();
In this example i am updating values, but it is a similar concept when just selecting values

As mentioned in other answers, for null "IS NULL" need to be used. Here is some convenience code for having both null and strings (I'm using delete in the example but the same can be done for other methods, e.g. query):
public void deleteSomething(String param1, String param2, String param3) {
ArrayList<String> queryParams = new ArrayList<>();
mDb.delete(TABLE_NAME,
COLUMN_A + getNullSafeComparison(param1, queryParams) + "AND " +
COLUMN_B + getNullSafeComparison(param2, queryParams) + "AND " +
COLUMN_C + getNullSafeComparison(param3, queryParams),
queryParams.toArray(new String[0]));
}
private String getNullSafeComparison(String param, List<String> queryParams) {
if (param == null) {
return " IS NULL ";
} else {
queryParams.add(param);
return " = ? ";
}
}

You can bind NULL values to SQLiteStatement:
SQLiteDatabase db = getWritableDatabase();
SQLiteStatement stmt = db.compileStatement("UPDATE table SET " +
"parameter=? WHERE id=?");
if (param == null)
stmt.bindNull(1);
else
stmt.bindString(1, param);
stmt.execute();
stmt.close();
db.close();

Android SQLite Query: Trouble with WHERE clause

Please let me know why my where clause isn't working. I tried using the query instead of rawquery but no luck.
try {
String categoryex = "NAME";
DBHelper dbHelper = new DBHelper(this.getApplicationContext());
MyData = dbHelper.getWritableDatabase();
Cursor c = MyData.rawQuery("SELECT * FROM " + tableName + where Category = '+categoryex'" , null);
if (c != null ) {
if (c.moveToFirst()) {
do {
String firstName = c.getString(c.getColumnIndex("Category"));
String age = c.getString(c.getColumnIndex("Text_Data"));
results.add( firstName + " Directions: " + age);
}while (c.moveToNext());
}
}
} catch (SQLiteException se ) {
Log.e(getClass().getSimpleName(), "Could not create or Open the database");
} finally {
if (MyData != null)
MyData.execSQL("DELETE FROM " + tableName);
MyData.close();
}

try... (you left out a double-quote before where.
Cursor c = MyData.rawQuery("SELECT * FROM " + tableName + " where Category = '" +categoryex + "'" , null);

I think you should use rawQuery in this form:
rawQuery("SELECT * FROM ? where Category = ?", new String[] {tableName, categoryex});
I think it's more secure this way.

Your quotes are buggered:
Cursor c = MyData.rawQuery("SELECT * FROM " + tableName + " where Category = '" + categoryex + "'" , null);
You also should read up on SQL injection attacks.

it will be more easy if you use this technique instead of rawQuery,its easy way change your table name, columns and where conditions accordingly.
public ArrayList<Invitees> getGroupMembers(String group_name) {
ArrayList<Invitees> contacts = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
String[] projection = {COLUMN_CONTACT, COLUMN_PHONE_NUMBER};
String selection = COLUMN_GROUP_NAME + "=?";
String[] selectionArgs = {group_name};
Cursor cursor = db.query(GROUPS_TABLE_NAME, projection, selection, selectionArgs, null, null, null);
if (cursor.moveToFirst()) {
do {
Invitees invitees = new Invitees();
invitees.setUserName(cursor.getString(cursor.getColumnIndexOrThrow(COLUMN_CONTACT)));
invitees.setInviteePhone(cursor.getString(cursor.getColumnIndexOrThrow(COLUMN_PHONE_NUMBER)));
contacts.add(invitees);
} while (cursor.moveToNext());
}
return contacts;
}

rawQuery(query, selectionArgs)

I want to use select query for retrieving data from table. I have found, rawQuery(query, selectionArgs) method of SQLiteDatabase class to retrieve data. But I don't know how the query and selectionArgs should be passed to rawQuery method?

rawQuery("SELECT id, name FROM people WHERE name = ? AND id = ?", new String[] {"David", "2"});
You pass a string array with an equal number of elements as you have "?"

Maybe this can help you
Cursor c = db.rawQuery("query",null);
int id[] = new int[c.getCount()];
int i = 0;
if (c.getCount() > 0)
{
c.moveToFirst();
do {
id[i] = c.getInt(c.getColumnIndex("field_name"));
i++;
} while (c.moveToNext());
c.close();
}

One example of rawQuery - db.rawQuery("select * from table where column = ?",new String[]{"data"});

if your SQL query is this
SELECT id,name,roll FROM student WHERE name='Amit' AND roll='7'
then rawQuery will be
String query="SELECT id, name, roll FROM student WHERE name = ? AND roll = ?";
String[] selectionArgs = {"Amit","7"}
db.rawQuery(query, selectionArgs);

see below code it may help you.
String q = "SELECT * FROM customer";
Cursor mCursor = mDb.rawQuery(q, null);
or
String q = "SELECT * FROM customer WHERE _id = " + customerDbId ;
Cursor mCursor = mDb.rawQuery(q, null);

For completeness and correct resource management:
ICursor cursor = null;
try
{
cursor = db.RawQuery("SELECT * FROM " + RECORDS_TABLE + " WHERE " + RECORD_ID + "=?", new String[] { id + "" });
if (cursor.Count > 0)
{
cursor.MoveToFirst();
}
return GetRecordFromCursor(cursor); // Copy cursor props to custom obj
}
finally // IMPORTANT !!! Ensure cursor is not left hanging around ...
{
if(cursor != null)
cursor.Close();
}

String mQuery = "SELECT Name,Family From tblName";
Cursor mCur = db.rawQuery(mQuery, new String[]{});
mCur.moveToFirst();
while ( !mCur.isAfterLast()) {
String name= mCur.getString(mCur.getColumnIndex("Name"));
String family= mCur.getString(mCur.getColumnIndex("Family"));
mCur.moveToNext();
}
Name and family are your result