title: Android get sum of database column
body: <p>I need help with summing all the values in one of the columns(amount) in my database. i can a get a particular value. .but i need sum of a specific column, somebody tell me what I'm doing wrong</p>
  
  <p>This is my code</p>
  
  <pre><code>    Button button3 = (Button) findViewById(R.id.button3);
      button3.setOnClickListener(new OnClickListener() {          
         public void onClick(View v) {                
            DatabaseAdapter databaseAdapter = new DatabaseAdapter(getApplicationContext());
            databaseAdapter.open();
            ArrayList&lt;String&gt; records = databaseAdapter.fetchAllRecords();
            if (records.size() &gt; 0) {
                et.setText(records.get(0));
            }
            databaseAdapter.close();
        }
     });
  
      //Create our database by opening it and closing it
      DatabaseAdapter databaseAdapter = new DatabaseAdapter(getApplicationContext());
      databaseAdapter.open();
      databaseAdapter.close();
  } 
  
  private Object append(CharSequence text) {
      // TODO Auto-generated method stub
      return null;
  }
  
  /** Create a new dialog for date picker */
  @Override
  protected Dialog onCreateDialog(int id) {
      switch (id) {
         case DATE_DIALOG_ID:
           return new DatePickerDialog(this, pDateSetListener, pYear, pMonth, pDay);
      }
      return null;
  }
  }
  </code></pre>
  
  <p>This is the database part  <code>DatabaseAdapter.java</code></p>
  
  <pre><code>package com.example.androidtablayout;
  
  import java.util.ArrayList;
  import android.content.ContentValues;
  import android.content.Context;
  import android.database.Cursor;
  import android.database.SQLException;
  import android.database.sqlite.SQLiteDatabase;
  import android.text.Editable;
  
  public class DatabaseAdapter {
  
      private Context context;
      private SQLiteDatabase database;
      private DatabaseOpenHelper dbHelper;
  
      public DatabaseAdapter(Context context) {
         this.context = context;
      }
  
      public DatabaseAdapter open() throws SQLException {
         dbHelper = new DatabaseOpenHelper(context);
         database = dbHelper.getWritableDatabase();
         return this;
      }
  
      public void close() {
         dbHelper.close();
      }
  
  
      public long createRecord(String text,int j,String text1,String text2) {
          ContentValues contentValue = new ContentValues();       
          contentValue.put("date", text);     
          contentValue.put("amount", j);  
          contentValue.put("des", text1);
          contentValue.put("category", text2);
          return database.insert("Extable", null, contentValue);
      }
  
      public boolean updateRecord(long rowId,String text,int j,String text1,String text2) {
          ContentValues contentValue = new ContentValues();
          contentValue.put("date", text);     
          contentValue.put("amount", j);  
          contentValue.put("des", text1);
          contentValue.put("category", text2);
          return database.update("Extable", contentValue, "_id =" + rowId, null) &gt; 0;
      }
  
      public boolean deleteRecord(long rowId) {
          return database.delete("Extable", "_id =" + rowId, null) &gt; 0;
      }
  
      public ArrayList&lt;String&gt; fetchAllRecords() {
          Cursor cursor = database.query("Extable", new String[] { "_id", "date", "amount", "des", "category"},
                  null, null, null, null, null);      
          ArrayList&lt;String&gt; records = new ArrayList&lt;String&gt;();        
          cursor.moveToFirst();
          for (int i = 0; i &lt; cursor.getCount(); i++) {           
              records.add(cursor.getString(1));       
              cursor.moveToNext();
          }
          cursor.close();
          return records;
      }
  
      public String fetchRecord(long rowId) throws SQLException {
          Cursor mCursor = database.query(true, "Extable", new String[] { "_id",
                          "date","amount", "des","category" }, "_id ="+ rowId, null, null, null, null, null);
          if (mCursor != null) {
              mCursor.moveToFirst();
              return (mCursor.getString(1));
          }
          return null;
      }
  
      public Cursor rawQuery(String string, Object object) {
          // TODO Auto-generated method stub
          return null;
      }
  </code></pre>
  
  <p>Pls anyone help to me.
  Thank u</p>