Question

我正在使用的功能，从表中检索一个值，

public ArrayList selectValue(SQLiteDatabase sqliteDB, String contactEmail){ 
     Cursor c = sqliteDB.rawQuery("SELECT * FROM " + TABLE_NAME + " WHERE ContactEmail='"+contactEmail+"'",null); 
     if (c != null) { 
      if (c.moveToFirst()) { 
       do { 
        double contactId = c.getDouble(c.getColumnIndex("ContactId")); 
        results.add("ContactEmail: " +contactEmail+ ",ContactId: " + contactId); 
       }while (c.moveToNext()); 
      } 
     } 
     return results; 
    } 

但上面的函数从表中检索的所有值..不知道什么是错的查询..

我也试过硬编码这样的价值，

Cursor c = sqliteDB.rawQuery("SELECT * FROM " + TABLE_NAME + " WHERE ContactEmail='peter@peter.com'",null); 

，但是这也给所有行。我在这里错过了什么？请帮助

Answer 1

尝试做这样的：

SQLiteDatabase mDb; 
    DataBaseHelper mDbHelper; 
    mDbHelper = new DataBaseHelper(context); 
    mDb = mDbHelper.getWritableDatabase(); 
    Cursor cursor = mDb.query(TABLE_NAME, null, ContactEmail + " =? ", new String[] { "peter@peter.com" }, null, null, null); 
    //Continue with your code 


private static class DataBaseHelper extends SQLiteOpenHelper { 

     /* Create a helper object to create, open, and/or manage a database */ 
     DataBaseHelper(Context context) { 
      super(context, TABLE_NAME, null, DATABASE_VERSION); 
     } 

     /* Called when the database is created for the first time */ 
     @Override 
     public void onCreate(SQLiteDatabase db) { 
        //Your code 
     } 

      /* Called when the database needs to be upgraded*/ 
     @Override 
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
         //Your code 
     } 
} 

Answer 2

感谢您的答复人..我固定的问题..

这是我改变了代码，并得到了它的工作，

public String selectValue(SQLiteDatabase sqliteDB, String contactEmail){ 

     String contactId="Nothing"; 

     Cursor c = sqliteDB.rawQuery("SELECT * FROM " + TABLE_NAME + " where ContactEmail = '"+contactEmail+"'", null); 
     if (c != null) { 
      if (c.moveToFirst()) { 
       contactId = c.getString(c.getColumnIndex("ContactId")); 
      } 
     } 
     return contactId; 
    } 

再次感谢!!祝你有美好的一天！！