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你好我創建一個應用程序的健身鍛鍊,在那裏的信息可以保存到2個表(TABLE_CARDIO對心臟活動和TABLE_WEIGHTS的重量訓練活動)返回所有字段。下面是兩個表的結構:寫一個SQL查詢,從2個sqlite的表(Android應用程序)
public static final String DATABASE_NAME = "FitnessTracker.db";
public static final String TABLE_WEIGHTS = "saved_workout_weights";
public static final String COL_1 = "ID";
public static final String COL_2 = "DATE";
public static final String COL_3 = "EXERCISE";
public static final String COL_4 = "WEIGHT";
public static final String COL_5 = "REPS";
public static final String COL_6 = "SETS";
public static final String TABLE_CARDIO = "saved_workout_cardio";
public static final String COL_1a = "ID";
public static final String COL_2a = "DATE";
public static final String COL_3a = "TIME";
然後我有以下方法用於從兩個表中選擇所有的數據(這正是我需要的)查詢:
public Cursor getWorkoutData() {
SQLiteDatabase db = this.getWritableDatabase();
String query = "SELECT * FROM " + TABLE_CARDIO + "FULL OUTER JOIN " + TABLE_WEIGHTS + "ON" + TABLE_CARDIO.DATE = TABLE_WEIGHTS.DATE; ;
Cursor result = db.rawQuery(query,null);
return result;
}
,你可以在查詢中,請參閱我試圖使用'DATE'字段作爲外鍵來加入2個表。不過,android studio會突出顯示'DATE'爲紅色,並拋出錯誤'無法解析符號'。
我知道這裏有一些類似的問題,但我一直無法在我的方案中實施任何解決方案。任何幫助,將不勝感激!
太棒了,這正是我需要知道的。謝謝! –