Android SQLITE！ 从同一表查询多个数据（列）

Question

public class DatabaseHelper4 extends SQLiteOpenHelper {
private final static String DBNAME = "Bidprice";
private final static int DBVERSION = 2;

SQLiteDatabase mDB2;

public final static String TBL_BID = "bidprice";
public final static String COL_BID_ID = BaseColumns._ID;
public final static String COL_BID_PRICE = "pricebid";
public final static String COL_BID_NAME = "namebid";


private String crt_tbl_bidprice = "CREATE TABLE IF NOT EXISTS " + TBL_BID + "(" +
        COL_BID_ID + " INTEGER PRIMARY KEY, " +
        COL_BID_PRICE + " TEXT, " +
        COL_BID_NAME + " TEXT " +
        ")";

public DatabaseHelper4(Context context) {
    super(context, DBNAME, null, DBVERSION);
    mDB2 = this.getWritableDatabase();
}


@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(crt_tbl_bidprice);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

}

public long addPrice(String price,String nameprice) {
    ContentValues cv = new ContentValues();
    cv.put(COL_BID_PRICE,price);
    cv.put(COL_BID_NAME,nameprice);
    return mDB2.insert(TBL_BID,null,cv);
}



public Cursor getLatestPrice() {

    return mDB2.query(TBL_BID,null,null,null,null,null,COL_BID_PRICE + " DESC","1");
}

}

I am trying to query more than one data(column) from the table of this database. How do I go about it?I believe it has to do with the formatting of the query statement in my function of getLatestPrice()

Hope I could get some help.Much appreciated

Answer 1

for a start brother try something like this in the getLatestPrice part of yours

public Cursor getLatestPrice() {
  SQLiteDatabase db = this.getReadableDatabase();
  Cursor res =  db.rawQuery( "select * from "+TBL_BID, null);
  return res;    
}

This shall give you the cursor you require for now! with all the data in it from the table you want! and if you want to get any specific column/s and other stuff then you have to do like this for a start

public Cursor getLatestPrice() {
      SQLiteDatabase db = this.getReadableDatabase();

String[] projection = {
    COL_BID_PRICE,
    COL_BID_NAME
    };

Cursor res = db.query(
    TBL_BID,   // The table to query
    projection,             // The array of columns to return (pass null to get all)
    null,              // The columns for the WHERE clause
    null,          // The values for the WHERE clause
    null,                   // don't group the rows
    null,                   // don't filter by row groups
    null               // The sort order
    );

      return res;    
    }

For easier detail and setup reffer to this link here

For more advanced and google documentation on this part for android see! link here