Develop Reference

How use query() with WHERE clause?

I need to get the question, where the column : activity, lesson and screen are equal to eg: " 1", " 2" , "3".
Note: question is a column too.
My code should return a string = "4" but are returning:
android.database.sqlite.SQLiteCursor#547e1a74
Code:
databaseHelper = Database.getInstance(getApplicationContext());
long id4 = databaseHelper4.insertData("1", "2", "3","4", "5", "6", "7", "8");
String question = databaseHelper4.getQuestion("1", "2", "2");
Message.message(IntroActivity.this, question);
Database:
public String getQuestion(String activity, String lesson, String screen){
SQLiteDatabase db = helper.getWritableDatabase();
String[] columns = {DatabaseHelper.QUESTION};
Cursor cursor = db.query(DatabaseHelper.TABLE_NAME, columns, DatabaseHelper.ACTIVITY +
"=?" + " AND " + DatabaseHelper.LESSON + "=?" + " AND " + DatabaseHelper.SCREEN +
"=?", new String[]{activity, lesson, screen}, null, null, null, null);
return cursor.toString();
}

Here:
return cursor.toString();
Cursor.toString() method return String representation of Cursor instead of values which is contained by Cursor.
Get QUESTION Column value from cursor as:
cursor.moveToFirst();
String question = cursor.getString(cursor.getColumnIndex(
DatabaseHelper.QUESTION));

instead of returning cursor.toString(), you should return
cursor.getString(cursor.getColumnIndex(DatabaseHelper.QUESTION));
after you call cursor.moveToFirst();
public String getQuestion(String activity, String lesson, String screen){
SQLiteDatabase db = helper.getWritableDatabase();
String[] columns = {DatabaseHelper.QUESTION};
Cursor cursor = db.query(DatabaseHelper.TABLE_NAME, columns, DatabaseHelper.ACTIVITY +
"=?" + " AND " + DatabaseHelper.LESSON + "=?" + " AND " + DatabaseHelper.SCREEN +
"=?", new String[]{activity, lesson, screen}, null, null, null, null);
cursor.moveToFirst()
return cursor.getString(cursor.getColumnIndex(DatabaseHelper.QUESTION));;
}

filter a listview populated from SQLite

i added a filter to my listview ( populated from sqlite ). i am using this method to fetch the records from sqlite
public Cursor fetchServicesByName(String inputText, String c) throws SQLException {
db = this.getReadableDatabase();
Cursor mCursor = null;
if (inputText == null || inputText.length () == 0) {
mCursor = db.query(TABLE_SERVICE, new String[] {KEY_ID,KEY_NAME,
KEY_ADRESSE, KEY_EMAIL, KEY_NUMTEL, KEY_WEBSITE,KEY_IMAGE}, KEY_TYPE + "=?",
new String[] { c },null, null, null, null);
}
else {
mCursor = db.query(true, TABLE_SERVICE, new String[] {KEY_ID,KEY_NAME,
KEY_ADRESSE, KEY_EMAIL, KEY_NUMTEL, KEY_WEBSITE,KEY_IMAGE},
KEY_NAME + " like '%" + inputText + "%'" , null,
null, null, null, null);
}
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
this is working, but what i want to do is to filter by inputText and KEY_TYPE
i used this (instead of the last db.query ) but it didn't return anything
mCursor = db.query(TABLE_SERVICE, new String[] {KEY_ID,KEY_NAME,
KEY_ADRESSE, KEY_EMAIL, KEY_NUMTEL, KEY_WEBSITE,KEY_IMAGE},
KEY_NAME + " like ? and" + KEY_TYPE + " like ? " , new String[] { inputText, c},
null, null, null, null);

You need to check if your inputtext and keytype are null!
Aris your routine working when you fill out your inputtext and c vallue?

How to return multiple entries with same value from SQLite

This is what my database looks like, how would I return all of the rows that have the same string in the KEY_ALCOHOL column? After I get all of the rows, I need to randomly pick one and then display it.
I tried this:
DATABASE HELPER .JAVA
public Cursor getAlcohol(String alcohol) throws SQLException
{
Cursor mCursor =
myDataBase.query(true, DB_TABLE, new String[] {
KEY_ROWID,
KEY_ALCOHOL,
KEY_TYPE,
KEY_BRAND,
KEY_PRICE
},
KEY_ALCOHOL + "=" + alcohol,
null,
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
MAIN ACTIVITY .JAVA
myDbHelper.openDataBase();
Cursor c = myDbHelper.getAlcohol("Liquor");
if (c.moveToFirst())
{
do {
DisplayTitle(c);
} while (c.moveToNext());
}
myDbHelper.close();
}
public void DisplayTitle(Cursor c)
{
Toast.makeText(this,
"id: " + c.getString(0) + "\n" +
"ALCOHOL: " + c.getString(1) + "\n" +
"TYPE: " + c.getString(2) + "\n" +
"BRAND: " + c.getString(3) + "\n" +
"PRICE: " + c.getString(4),
Toast.LENGTH_LONG).show();
}
I was testing to see if this would simply return all of the rows with "Liquor" in the KEY_ALCOHOL column but instead it gave me a null pointer.
EDIT
Got it working!!
Here is what i came up with and it works!! Let me know if anything is wrong or you see a better way of doing it! Thanks everyone!
myDbHelper.openDataBase();
Cursor Test = myDbHelper.getAlcohol("Liquor");
int test7 = Test.getCount();
test9 = r.nextInt(test7);
Cursor c = myDbHelper.getTitle(test9);
if (c.moveToFirst())
DisplayTitle(c);
else
Toast.makeText(this, "No title found",
Toast.LENGTH_LONG).show();
myDbHelper.close();

I hope this works
public Cursor getAlcohol(String alcohol) throws SQLException
{
Cursor mCursor =
myDataBase.query(true, DB_TABLE, new String[] {
KEY_ROWID,
KEY_ALCOHOL,
KEY_TYPE,
KEY_BRAND,
KEY_PRICE
},
KEY_ALCOHOL + "=?",
new String[] { alcohol },
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
Look at structure
Cursor SQLiteDatabase.query(String table,
String[] columns,
String selection,
String[] selectionArgs,
String groupBy,
String having,
String orderBy,
String limit)
Your 'selection' was wrong. It resulted in WHERE KEY_ALCOHOL + "=" + alcohol = null since argument is separate.

Setting multiple Selections args in SQLite database query

How would i go about querying more than one selection arg? For example here is how my database is formatted
Here is the code i used to search with just one seletion arg:
public Cursor getType(String type) throws SQLException
{
Cursor mCursor =
db.query(true, DB_TABLE, new String[] {
KEY_ROWID,
KEY_ALCOHOL,
KEY_TYPE,
KEY_BRAND,
KEY_PRICE
},
KEY_TYPE + "=?",
new String[] { type },
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
But this only searches by KEY_TYPE, how would I set it so it searches by KEY_TYPE, KEY_ALCOHOL, and KEY_PRICE?

This may help you
public Cursor getType(String type) throws SQLException
{
Cursor mCursor =
db.query(true, DB_TABLE, new String[] {
KEY_ROWID,
KEY_ALCOHOL,
KEY_TYPE,
KEY_BRAND,
KEY_PRICE
},
KEY_TYPE + "=?" + " AND " + KEY_ALCOHOL + "=?" " AND " + KEY_PRICE + "=?",
new String[] { type,alcohol,price },
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}

Figured it out!! Thanks to #Rajendra for giving me some code to build off of! You can only add Strings into the selections args so i did this:
public Cursor getTest(String alcohol, String type, long price) throws SQLException
{
Cursor mCursor =
myDataBase.query(true, DB_TABLE, new String[] {
KEY_ROWID,
KEY_ALCOHOL,
KEY_TYPE,
KEY_BRAND,
KEY_PRICE
},
KEY_ALCOHOL + "=?" + " AND " + KEY_TYPE + "=?" + " AND " + KEY_PRICE + "<=" + price,
new String[] { alcohol, type},
null,
null,
null,
null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
And it works!!

SQLiteDatabase - How to use where clause?

public Cursor fetchTimetable() {
return mDb.query(DATABASE_TABLE_TIMETABLE, new String[] {TIMETABLE_ROWID, TIMETABLE_MODULECODE, TIMETABLE_MODULENAME, TIMETABLE_ROOM, TIMETABLE_LECTURER, TIMETABLE_TIME}, null, null, null, null, null);
}
For example if i wanted TIMETABLE_MODULECODE = 123. How would i do this, i have read its the first null. I have tried this below but still doesnt work
public Cursor fetchTimetable() {
String a = "TIMETABLE_CODE = ADD";
return mDb.query(DATABASE_TABLE_TIMETABLE, new String[] {TIMETABLE_ROWID, TIMETABLE_MODULECODE, TIMETABLE_MODULENAME, TIMETABLE_ROOM, TIMETABLE_LECTURER, TIMETABLE_TIME}, a, null, null, null, null);
}

My working example with where args (it's more clear with using it):
String [] settingsProjection = {
DBContract.Settings._ID,
DBContract.Settings.COLUMN_NAME_USER_ID,
DBContract.Settings.COLUMN_NAME_AUTO_LOGIN
};
String whereClause = DBContract.Settings.COLUMN_NAME_USER_ID+"=?";
String [] whereArgs = {userId.toString()};
Cursor c = db.query(
DBContract.Settings.TABLE_NAME,
settingsProjection,
whereClause,
whereArgs,
null,
null,
null
);

db.query
(
TABLE_NAME,
new String[] { TABLE_ROW_ID, TABLE_ROW_ONE, TABLE_ROW_TWO },
TABLE_ROW_ID + "=" + rowID,
null, null, null, null, null
);
TABLE_ROW_ID + "=" + rowID, here "=" is the where clause

What exactly does "still doesn't work" mean?
The following code should work just fine:
public Cursor fetchTimetable() {
String[] columnNames = new String[] {TIMETABLE_ROWID, TIMETABLE_MODULECODE, TIMETABLE_MODULENAME, TIMETABLE_ROOM, TIMETABLE_LECTURER, TIMETABLE_TIME};
String whereClause = "TIMETABLE_MODULECODE=123";
return mDb.query(DATABASE_TABLE_TIMETABLE, columnNames, whereClause, null, null, null, null);
}

the right syntax is
String[] projection= {column names};
String[] where={"values for where clause"}; //this must be array
public Cursor fetchTimetable() {
return mDb.query(TABLE_NAME, projrction, "columname"+"=?", where, null, null, null);
}

The simple way:
return mDb.rawQuery("SELECT * FROM myTable WHERE column1 = "+ someValue, null);

You can use Use this query:
SQLiteDatabase db = this.getReadableDatabase();
//Cursor cursorr = db.rawQuery(Query, null);
Cursor cursorr = db.rawQuery("select * from " + DATABASE_TABLE_EHS + " where " + TASK_ID + "='" + taskid + "'" , null);
if (cursorr.moveToFirst())
{
do {
// your code like get columns
}
while (cursorr.moveToNext());
}
}

If you're checking against a string value you'll want to wrap the string in quotes like below:
dbHelper.COL_EMAIL +"='"+givenEmail+"'",