How to get the first column data in sqlite database?

How to get the first column data in sqlite database? - android

I am trying to get the first column like below sql but my code show error.
SELECT subject FROM setting WHERE rowid=1
public void getSetting(){
result = "";
SQLiteDatabase db = myDbHelper.getReadableDatabase();
Cursor c = db.query(true, "setting", new String[] {"subject", "language", "selection"}, "row=1", null, null, null, null, null);
for(c.moveToFirst();!(c.isAfterLast());c.moveToNext()){
result = result + c.getString(0);
result = result + c.getString(0);
result = result + c.getString(0);
}
if (c.getCount() == 0)
result = result + "result not found";
c.close();
db.close();
myDbHelper.close();
}

Your stuff is a little hard to understand, but i think i have an idea what you want. You what to get a cursor to return only one row where the row's id is a specific value. And you only want the string from one column of that returned row. I assume that the primary issue is your designation of the _id column that you're looking for. You either called it row or rowid, you gotta double-check that.
Moreover, i hope the following re-write clears up further issues that you might have.
public String getSetting() {
String result = "";
String[] columns = {"subject"};
String[] selectionArgs = {"1"};
String LIMIT = String.valueOf(1); // <-- number of results we want/expect
SQLiteDatabase db = myDbHelper.getReadableDatabase();
Cursor c = db.query(true, "setting", columns, "rowid = ?", selectionArgs, null, null, null, LIMIT);
if (c.moveToFirst()) {
result = result + c.getString(0);
} else {
result = result + "result not found";
}
c.close();
myDbHelper.close();
return result;
}
Moreover, moreover. If you get an error you should post it so that we have an idea what's going on.

Related

search sqlite with multiple columns

Hi every one I'm trying to search my sqlite data base which has 4 columns but the app crashes and the log error is :-
Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
I'm wondering if there is a method to search sqlite data base with multiple columns and with single columns.
The code for the cursor is :-
cursor = mReadableDB.query(WORD_LIST_TABLE, columns, where, whereArgs, null, null, null);
DataBase Code is :
public Cursor search(String searchString) {
String[] columns = new String[]{KEY_WORD};
String where = KEY_WORD + " LIKE ?";
searchString = "%" + searchString + "%";
String[] whereArgs = new String[]{searchString};
Cursor cursor = null;
if (mReadableDB == null) {
mReadableDB = getReadableDatabase();
}
cursor = mReadableDB.query(WORD_LIST_TABLE, columns, where, whereArgs, null, null, null);
return cursor;
}
and the search class is :
public void showResult(View view) {
String word = editText_search.getText().toString();
textView.setText("Result for " + word + ":\n\n");
Cursor cursor = mDataBase.search(word);
cursor.moveToFirst();
if (cursor != null & cursor.getCount() > 0) {
int index;
String result;
do {
index = cursor.getColumnIndex(mDataBase.KEY_WORD);
result = cursor.getString(index);
textView.append(result + "\n");
} while (cursor.moveToNext());
cursor.close();
} else {
textView.append("no result");
}
}

Your cursor does not return anything. this is how I usually use database in android: by using .rawQuery(); and SQLite.
e.g.
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM tasks WHERE id = " + id, null);
And you can also check if the cursor is empty or not by calling cursor.moveToFirst();.
If cursor was empty, the method returns false. else it returns true.
After checking that, you can go to the row that you want by using cursor.move(rowNumber); and get the value of the column you want with get methods e.g. cursor.getString(1);

how to use where clause in cursor query in sqlite

I want only particular rows that has "E" inside the column "TX_IDT". I used the following code but apps stops. In logcat the error says it is at db.query line.
public Cursor getAllRows( ) {
String where = null;
SQLiteDatabase db = helper.getReadableDatabase();
String[] columns = { VivzHelper.UID, helper.UID,helper.NAME,helper.TX_IDT};
String whereClause = "TX_IDT = ? ";
String[] whereArgs = new String[] { "E" };
Cursor c = db.query( VivzHelper.TABLE_NAME, columns,whereClause,whereArgs, null, null, NAME + " ASC"); // for out btn
if (c != null) {
c.moveToFirst();
}
return c;
}
`

Seems like you want record's containing "E" ,
Try this
Cursor c = db.query(VivzHelper.TABLE_NAME, columns, helper.TX_IDT +" LIKE '%E%' ", null, null, null, null);

How do I select a specific string from an SQL database?

I've spent some hours on trying to solve this but the only answer I get is that I can't select from a string? Is that so? How do I do it otherwise? Here's my code:
public String getHotness(String l) {
// TODO Auto-generated method stub
String[] columns = new String []{ KEY_ROWID, KEY_NAME, KEY_HOTNESS};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "=" + l, null, null, null, null);
int iHotness = c.getColumnIndex(KEY_HOTNESS);
if (c != null){
c.moveToFirst();
String hotness = c.getString(iHotness);
return hotness;
}
return null;
}
Where l is a name of a person in my database. How would I select and get information from this person by his name?
Thanks! You guys are the best!

You can select only records that fit a specific criteria using the WHERE clause for the select. In case of SQLiteDatabase#query() method, you need to use the third parameter.
Other considerations:
You should use parameters instead of concatenating the values to avoid common issues (like SQL injections).
No need to check if returned Cursor is null, it never is (as the documentation also states).
Also you should close your Cursor before returning from the method.
Example:
final String theName = "The person name";
Cursor c = null;
try {
c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + " = ?", new String[]{theName}, null, null, null);
if (c.moveToNext()) {
// Do your stuff
}
} finally {
if (c != null) {
c.close();
}
}`
Note that previous query will only match rows where KEY_NAME column is exactly theName value. If you want to search by names that include theName value, you need to use LIKE operator instead.
final String likeName = "%" + theName + "%";
final Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_NAME + " LIKE ?", new String[]{likeName}, null, null, null);

LIKE is what you are looking for. % means anything BEFORE yourname is matching. ?yourname means only 1 char before. if you make sure that the name matches exactly you will need to use name = 'yourname' instead.
Cursor c = null;
try {
c = ourDatabase.rawQuery("SELECT * from yourtable where name LIKE '%yourname%', null);
if (c != null && c.getCount() > 0 && c.moveToFirst()) {
do {
c.getString(....);
} while (c.moveToNext());
}
} catch (Exception e) { e.printStackTrace(); }
finally {
if (c != null) c.close();
}

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

How do I order my SQLITE database in descending order, for an android app?

What is the most efficient method of showing my data in descending order?
public String getRank() {
String[] rank = new String[]{ KEY_ROWID };
Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, null); //reading information from db.
String rankResult = "";
int iRow = c.getColumnIndex(KEY_ROWID); //Cursor looking for column setting equal to these ints.
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
//Move to first row - where cursor starts and moves to next row as long it is not after last row.
rankResult = rankResult + c.getString(iRow) + "\n";
//Returning value of row that it is currently on.
}
return rankResult; //returning result
}
public String getName() {
String[] name = new String[]{ KEY_NAME };
Cursor c = scoreDb.query(DATABASE_TABLE, name, null, null, null, null, null); //reading information from db.
String nameResult = "";
int iRow1 = c.getColumnIndex(KEY_NAME); //Cursor looking for column setting equal to these ints.
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
//Move to first row - where cursor starts and moves to next row as long it is not after last row.
nameResult = nameResult + c.getString(iRow1) + "\n";
//Returning value of row that it is currently on.
}
return nameResult; //returning result
}
public String getScore() {
String[] score = new String[]{ KEY_SCORE };
Cursor c = scoreDb.query(DATABASE_TABLE, score, null, null, null,null, null); //reading information from db.
String scoreResult = "";
int iRow2 = c.getColumnIndex(KEY_SCORE); //Cursor looking for column setting equal to these ints.
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()) {
//Move to first row - where cursor starts and moves to next row as long it is not after last row.
scoreResult = scoreResult + c.getString(iRow2) + "\n";
//Returning value of row that it is currently on.
}
return scoreResult; //returning result
}

Query has two syntax, the syntax you are using, last column represents orderBy, you just need to specify on what column you want to do orderBy +"ASC" (or) orderBy +"DESC"
Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, yourColumn+" DESC");
Refer this documentation to understand more about query() method.

return database.rawQuery("SELECT * FROM " + DbHandler.TABLE_ORDER_DETAIL +
" ORDER BY "+DbHandler.KEY_ORDER_CREATED_AT + " DESC"
, new String[] {});

Cursor c = scoreDb.query(Table_Name, score, null, null, null, null, Column+" DESC");
Try this

According to docs:
public Cursor query (String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy, String limit);
and your ORDER BY param means:
How to order the rows, formatted as an SQL ORDER BY clause
(excluding the ORDER BY itself). Passing null will use the default
sort order, which may be unordered.
So, your query will be:
Cursor cursor = db.query(TABLE_NAME, null, null,
null, null, null, KEY_ITEM + " DESC", null);

public List getExpensesList(){
SQLiteDatabase db = this.getWritableDatabase();
List<String> expenses_list = new ArrayList<String>();
String selectQuery = "SELECT * FROM " + TABLE_NAME ;
Cursor cursor = db.rawQuery(selectQuery, null);
try{
if (cursor.moveToLast()) {
do{
String info = cursor.getString(cursor.getColumnIndex(KEY_DESCRIPTION));
expenses_list.add(info);
}while (cursor.moveToPrevious());
}
}finally{
cursor.close();
}
return expenses_list;
}
This is my way of reading the record from database for list view in descending order. Move the cursor to last and move to previous record after each record is fetched. Hope this helps~

Cursor c = myDB.rawQuery("SELECT distinct p_name,p_price FROM products order by Id desc",new String[]{});
this works for me!!!

you can do it with this
Cursor cursor = database.query(
TABLE_NAME,
YOUR_COLUMNS, null, null, null, null, COLUMN_INTEREST+" DESC");

SQLite ORDER BY clause is used to sort the data in an ascending or descending order, based on one or more columns.
Cursor c = scoreDb.query(DATABASE_TABLE, rank, null, null, null, null, yourColumn+" DESC");
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(
TABLE_NAME,
rank,
null,
null,
null,
null,
COLUMN + " DESC",
null);

We have one more option to do order by
public Cursor getlistbyrank(String rank) {
try {
//This can be used
return db.`query("tablename", null, null, null, null, null, rank +"DESC",null );
OR
return db.rawQuery("SELECT * FROM table order by rank", null);
} catch (SQLException sqle) {
Log.e("Exception on query:-", "" + sqle.getMessage());
return null;
}
}
You can use this two method for order

This a terrible thing! It costs my a few hours!
this is my table rows :
private String USER_ID = "user_id";
private String REMEMBER_UN = "remember_un";
private String REMEMBER_PWD = "remember_pwd";
private String HEAD_URL = "head_url";
private String USER_NAME = "user_name";
private String USER_PPU = "user_ppu";
private String CURRENT_TIME = "current_time";
Cursor c = db.rawQuery("SELECT * FROM " + TABLE +" ORDER BY " + CURRENT_TIME + " DESC",null);
Every time when I update the table , I will update the CURRENT_TIME for sort.
But I found that it is not work.The result is not sorted what I want.
Finally, I found that, the column "current_time" is the default row of sqlite.
The solution is, rename the column "cur_time" instead of "current_time".

About efficient method. You can use CursorLoader. For example I included my action. And you must implement ContentProvider for your data base. https://developer.android.com/reference/android/content/ContentProvider.html
If you implement this, you will call you data base very efficient.
public class LoadEntitiesActionImp implements LoaderManager.LoaderCallbacks<Cursor> {
public interface OnLoadEntities {
void onSuccessLoadEntities(List<Entities> entitiesList);
}
private OnLoadEntities onLoadEntities;
private final Context context;
private final LoaderManager loaderManager;
public LoadEntitiesActionImp(Context context, LoaderManager loaderManager) {
this.context = context;
this.loaderManager = loaderManager;
}
public void setCallback(OnLoadEntities onLoadEntities) {
this.onLoadEntities = onLoadEntities;
}
public void loadEntities() {
loaderManager.initLoader(LOADER_ID, null, this);
}
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(context, YOUR_URI, null, YOUR_SELECTION, YOUR_ARGUMENTS_FOR_SELECTION, YOUR_SORT_ORDER);
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
}
#Override
public void onLoaderReset(Loader<Cursor> loader) {
}

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How to get the first column data in sqlite database? - android

Related

search sqlite with multiple columns

how to use where clause in cursor query in sqlite

How do I select a specific string from an SQL database?

rawQuery(query, selectionArgs)

How do I order my SQLITE database in descending order, for an android app?

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