获取表列总数

Question

我是新手在Java编程，所以我需要一些帮助…我在做这个累加的事情...

就像这样..

Score             Accumulated
10                10
40                50
60                110
and so on.......

这里有我的代码..。

public int accumulateScores(){

        db = this.getReadableDatabase();

        String query = "SELECT score, (SELECT sum(score) FROM "
                + TABLE_NAME+ ")" + " AS accumulated" + " FROM " + TABLE_NAME;
        Cursor cursor = db.rawQuery(query, null);

        if (cursor != null)
            cursor.moveToFirst();
            Score score = new Score(Integer.parseInt(cursor.getString(0)), cursor.getInt(1));




    }

我应该怎么做才能返回列得分的总和。提前谢谢..任何帮助都将深表感谢..

Answer 1

这应该会以一种相当简单的方式完成所需的操作，只需将所有行ID小于当前行的行求和即可。如果你在表中有一个自动递增的键，你可能想要使用那个键来获得一个更可预测的分数排序。

SELECT Score, 
   (SELECT SUM(Score) 
    FROM table_name a 
    WHERE rowid <= table_name.rowid
   ) Accumulated
FROM table_name
ORDER BY rowid

An SQLfiddle to test with。

编辑:基于你的错误样本；

SELECT score, 
   (SELECT SUM(score) 
    FROM score_table a
    WHERE a.id <= score_table.id
   ) Accumulated
FROM score_table
ORDER BY id

Another SQLfiddle。

Answer 2

您应该使用Google more并键入以下代码

SELECT SCORE，(SELECT SUM(SCORE) FROM table_name PATING WHERE rowid <=table_name.rowid )从table_name ORDER BY rowid累积