Question

我的SQLite数据库中有两个表。我试图从table1中选择三个随机行，从table2中选择三个随机行，并在listView中交替使用它们。

（前） table1随机行 table2随机行 table1随机行 table2随机行 table1随机行 table2随机行

由于某种原因，它不会交替listView中每个表的行。它按照自己想要的顺序放置它们。

这是我选择行并将它们插入所选表格的代码：

while (x <= 2) {
                    cursor1 = db.rawQuery("SELECT * FROM table1 ORDER BY RANDOM() LIMIT 1", null);
                    cursor1.moveToFirst();
                    rowId = cursor1.getInt(cursor1.getColumnIndex("_id"));
                    dbHandler.getWritableDatabase().execSQL("INSERT INTO chosen SELECT * FROM table1 WHERE _id = '" + rowId + "'");
                    dbHandler.getWritableDatabase().execSQL("UPDATE chosen SET _id = '" + newID + "' WHERE _id = '" + rowId + "'");
                    newID++;

                    cursor2 = db.rawQuery("SELECT * FROM table2 ORDER BY RANDOM() LIMIT 1", null);
                    cursor2.moveToFirst();
                    rowId = cursor2.getInt(cursor2.getColumnIndex("_id"));
                    dbHandler.getWritableDatabase().execSQL("INSERT INTO chosen SELECT * FROM table2 WHERE _id = '" + rowId + "'");
                    dbHandler.getWritableDatabase().execSQL("UPDATE chosen SET _id = '" + newID + "' WHERE _id = '" + rowId + "'");
                    newID++;

                    x++;
                }
                cursor1.close();
                cursor2.close();

这是我用来选择填充listView的数据

Cursor cursor = db.rawQuery("SELECT _id, value FROM chosen ORDER BY _id", null);

非常感谢任何帮助！

Answer 1

想出来。我让它变得比它需要的更复杂。这是我最终做的事情：

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确保所选表中的行id列是自动增量，并保持listview查询相同：

    while (x <= 2) {
                    dbHandler.getWritableDatabase().execSQL("INSERT INTO chosen (value1, value2, value3) SELECT value1, value2, value3 FROM table1 ORDER BY RANDOM() LIMIT 1, null);
                    dbHandler.getWritableDatabase().execSQL("INSERT INTO chosen (value1, value2, value3) SELECT value1, value2, value3 FROM table2 ORDER BY RANDOM() LIMIT 1, null);
                    x++;
                    }

简单得多 - 而且效果很好！

从SQLite DB交替进入ListView的随机行 - 顺序不正确

1 个答案: