Android SQLite SUM, бросает NullPointer

Question

, поэтому я работаю над приложением, и я только начал изучать SQLite для Android, видимо, я застрял уже 3 дня по одной проблеме. Всякий раз, когда я пытаюсь запустить запрос в SUM Up поля из таблицы, где месяц равен определенному месяцу, я получаю NullPointer.

package com.example.droid; 
import java.text.SimpleDateFormat; 
import java.util.Calendar; 

import com.example.droid.SqDb; 

import android.accounts.Account; 
import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.SQLException; 
import android.database.sqlite.SQLiteDatabase; 
import android.text.format.DateFormat; 
import android.util.Log; 


public class DbCon { 

    private static SQLiteDatabase database; 
    private SqDb SqHelper; 
    private String[] UserColumns = 
     { 
      SqDb.ACCOUNT_ID, 
      SqDb.ACCOUNT_NAME, 
      SqDb.ACCOUNT_USERNAME, 
      SqDb.ACCOUNT_PASSWORD, 
      SqDb.ACCOUNT_AGE, 
      SqDb.ACCOUNT_CITY, 
      SqDb.ACCOUNT_COUNTRY 
     }; 
    private String [] GuestColumns = 
     { 
      SqDb.GUEST_ID, 
      SqDb.GUEST_NAME 
     }; 
    private String [] TransColumns = 
     { 
      SqDb.TRAN_ID, 
      SqDb.TRAN_DESC, 
      SqDb.TRAN_TYPE, 
      SqDb.TRAN_TIME, 
      SqDb.TRAN_DAY, 
      SqDb.TRAN_MON, 
      SqDb.TRAN_YEAR, 
      SqDb.TRAN_CAT, 
      SqDb.TRAN_VAL 
     }; 

    private static DbCon myDCon; 

    DbCon(Context context) 
    { 
     SqHelper = SqDb.getInstance(context); 
    } 

    public static DbCon getInstance(Context context) 
    { 
     if(myDCon == null) 
      { 
      myDCon = new DbCon(context.getApplicationContext()); 
      } 
     return myDCon; 
    } 

    public void open() throws SQLException 
    { 
     database = SqHelper.getWritableDatabase(); 
    } 

    public void close() 
    { 
     SqHelper.close(); 
    } 

    public void createUser(String username, String password, String name, String Age, String City, String Country) 
    { 
     ContentValues values = new ContentValues(); 
     values.put(SqDb.ACCOUNT_USERNAME, username); 
     values.put(SqDb.ACCOUNT_PASSWORD, password); 
     values.put(SqDb.ACCOUNT_NAME, name); 
     values.put(SqDb.ACCOUNT_AGE, Age); 
     values.put(SqDb.ACCOUNT_CITY, City); 
     values.put(SqDb.ACCOUNT_COUNTRY, Country); 
     database.insert(SqDb.ACCOUNT, null, values); 
    } 

    public void createGuest(String name) 
    { 
     ContentValues values = new ContentValues(); 
     values.put(SqDb.GUEST_NAME, name); 
     database.insert(SqDb.GUEST, null, values); 
     } 

    public void AddTask(String desc, String type, String cat, double Value) 
    { 
     ContentValues values = new ContentValues(); 
     values.put(SqDb.TRAN_DESC, desc); 
     values.put(SqDb.TRAN_TYPE, type); 
     values.put(SqDb.TRAN_CAT, cat); 
     values.put(SqDb.TRAN_VAL, Value); 
     SimpleDateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss"); 
     Calendar cal = Calendar.getInstance(); 
     String timedata = df.format(cal.getTime()); 
     String[] whens = timedata.split(" "); 
     String time = whens[1]; 
     String[] dates = whens[0].split("/"); 
     values.put(SqDb.TRAN_TIME, time); 
     values.put(SqDb.TRAN_DAY, dates[2]); 
     values.put(SqDb.TRAN_MON, dates[1]); 
     values.put(SqDb.TRAN_YEAR, dates[0]); 
     database.insert(SqDb.TRAN, null, values); 
    } 
    Calendar cal = Calendar.getInstance(); 
    public int getMonthInt(){ 
     int month = cal.get(Calendar.MONTH); 
     return month; 
    } 
    public double CountMonthExp() 
    { 
     double din = 0; 
     this.open(); 
     Cursor c = database.rawQuery("SELECT sum("+SqDb.TRAN_VAL+") as"+SqDb.TRAN_VAL+" FROM "+SqDb.TRAN+" WHERE "+SqDb.TRAN_TYPE+"=EXPENDITURE and "+SqDb.TRAN_MON+"=3", null); 
     if(c.moveToFirst()){ 
      din = c.getDouble(0); 
     } 
     else{ 
      din = 0; 
     } 
     return din; 
    } 


} 

Любые предложения? И да, таблица создана хорошо и работает, я тестировал вставку записей, отлично работает.

Здесь ошибка:

03-19 00:18:38.119: E/AndroidRuntime(19822): FATAL EXCEPTION: main 03-19 00:18:38.119: E/AndroidRuntime(19822): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.droid/com.example.droid.Hist_act}: android.database.sqlite.SQLiteException: no such column: EXPENDITURE: , while compiling: SELECT sum(tran_val) astran_val FROM tran WHERE tran_type=EXPENDITURE and tran_mon=3 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.os.Handler.dispatchMessage(Handler.java:99) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.os.Looper.loop(Looper.java:130) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.ActivityThread.main(ActivityThread.java:3687) 03-19 00:18:38.119: E/AndroidRuntime(19822): at java.lang.reflect.Method.invokeNative(Native Method) 03-19 00:18:38.119: E/AndroidRuntime(19822): at java.lang.reflect.Method.invoke(Method.java:507) 03-19 00:18:38.119: E/AndroidRuntime(19822): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 03-19 00:18:38.119: E/AndroidRuntime(19822): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 03-19 00:18:38.119: E/AndroidRuntime(19822): at dalvik.system.NativeStart.main(Native Method) 03-19 00:18:38.119: E/AndroidRuntime(19822): Caused by: android.database.sqlite.SQLiteException: no such column: EXPENDITURE: , while compiling: SELECT sum(tran_val) astran_val FROM tran WHERE tran_type=EXPENDITURE and tran_mon=3 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:92) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteCompiledSql.(SQLiteCompiledSql.java:65) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:83) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteQuery.(SQLiteQuery.java:49) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:42) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1356) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1324) 03-19 00:18:38.119: E/AndroidRuntime(19822): at com.example.droid.DbCon.CountMonthExp(DbCon.java:122) 03-19 00:18:38.119: E/AndroidRuntime(19822): at com.example.droid.Hist_act.onCreate(Hist_act.java:42) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 03-19 00:18:38.119: E/AndroidRuntime(19822): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615) 03-19 00:18:38.119: E/AndroidRuntime(19822): ... 11 more

Answer 1

Я бы сказал, что есть по крайней мере две проблемы:

SELECT sum(tran_val) astran_val FROM tran WHERE tran_type=EXPENDITURE and tran_mon=3 

Я подозреваю, вы имеете в виду что-то вроде:

SELECT sum(tran_val) as tran_val FROM tran WHERE tran_type='EXPENDITURE' and tran_mon=3 

Я уверен, что вы сможете изменить код самостоятельно, чтобы добиться этих настроек.