Question

如果我在这样的数据库中有4行。

 |____A____|____B_____|
 |   a1    |    b1    |
 |   a2    |    b2    |
 |   a3    |    b3    |
 |   a4    |    b4    |

但我需要添加NO列来显示10行，以获取每行的序列号

 __NO__|____A____|____B_____|
   1   |   a1    |    b1    |
   2   |   a2    |    b2    |
   3   |   a3    |    b3    |
   4   |   a4    |    b4    |
   5   |         |          |
   6   |         |          |
   7   |         |          |
   8   |         |          |
   9   |         |          |
  10   |         |          |

如何通过sql server查询？

Answer 1

在这里小提琴：http://sqlfiddle.com/#!3/9a9dd/1

public void Showdata(View view)
    {
        Cursor c = db.rawQuery("SELECT * FROM Student2", null);
        int count = c.getCount();
        c.moveToFirst();
        TableLayout tablelayout = new TableLayout(getApplicationContext());
        tablelayout.setVerticalScrollBarEnabled(true);
        TableRow tablerow;
        TextView textview, textview1, textview3, textview5;
        tablerow = new TableRow(getApplicationContext());

        textview = new TextView(getApplicationContext());
        textview.setText("Name");
        textview.setTextColor(Color.RED);
        textview.setTypeface(null, Typeface.BOLD);
        textview.setPadding(20, 20, 20, 20);
        tablerow.addView(textview);


        textview5 = new TextView(getApplicationContext());
        textview5.setText("Email");
        textview5.setTextColor(Color.RED);
        textview5.setTypeface(null, Typeface.BOLD);
        textview5.setPadding(20, 20, 20, 20);
        tablerow.addView(textview5);
        tablelayout.addView(tablerow);

        for(Integer j=0; j< count; j++)
        {
            tablerow = new TableRow(getApplicationContext());

            textview1 = new TextView(getApplicationContext());
            textview1.setText(c.getString(c.getColumnIndex(name)));


            textview3 = new TextView(getApplicationContext());
            textview3.setText(c.getString(c.getColumnIndex(email)));

            textview1.setPadding(20, 20, 20, 20);
            textview3.setPadding(20, 20, 20, 20);

            tablerow.addView(textview1);
            tablerow.addView(textview3);

            tablelayout.addView(tablerow);
            c.moveToNext();
        }
        setContentView(tablelayout);
        db.close();
    }

Answer 2

这是另一种不使用递归cte和LEFT JOIN的方法。

SQL Fiddle

;WITH Cte AS(
    SELECT 
        NO = ROW_NUMBER() OVER (ORDER BY A, B), A, B
    FROM tbl
    UNION ALL
    SELECT
        t.n, NULL, NULL
    FROM (VALUES
        (11), (12), (13), (14), (15), (16), (17), (18), (19), (20)
    )t(n)
),
CteFinal AS(
    SELECT *, rn = ROW_NUMBER() OVER (ORDER BY NO)
    FROM Cte
)
SELECT
    rn AS NO, A, B
FROM CteFinal
WHERE rn < = 10

如何在sql中获取固定数量的行

2 个答案: