Question

我试图通过在where子句中传递“id”号来从表中检索数据 sqlite android，但是得到空的结果。

如果我将另一个字段（名称，数字）作为where子句传递。它工作正常，但不适用于id。

这是表格的代码：

public final String field_id = "id";
    public final String field_name = "name";
    public final String field_no = "no";

String create_query = "CREATE TABLE " + TABLE_NAME + "("
            + field_id + " INTEGER PRIMARY KEY autoincrement,"
            +field_name+ " TEXT,"
            + field_no + " TEXT"
            + ")";

以下是检索数据的代码

Cursor editData(String id)
    {

        Log.d(TAG, "editData() called");
        SQLiteDatabase db = this.getReadableDatabase();

        String search_query = "SELECT * FROM "+ TABLE_NAME +" WHERE id=?";
        Cursor cursor = db.rawQuery(search_query,new String []{id});
        if(cursor == null)
        {
            Log.d(TAG, "cursor is NULL");
            return null;
        }
        return cursor;
    }

以下是我使用此结果的方法

            DBHelper mDB = new DBHelper(this);
            Cursor mCursor = mDB.editData(id_name.getText().toString());

        if(mCursor.moveToFirst())
        {
            Log.d("EditActivity", "cursor moved to first");
            Log.d("TAG",String.format("%d", mCursor.getCount()));

            //Solved this by using Do...While loop instead of while
            while(mCursor.moveToNext())
            {
                Log.d("EditActivity", "cursor moved to next");
                Log.d(mCursor.getColumnName(0), mCursor.getString(0));
                Log.d(mCursor.getColumnName(1), mCursor.getString(1));
                Log.d(mCursor.getColumnName(2), mCursor.getString(2));
            }

        }

我们不能在sqlite的where子句中使用自动生成的id吗？对此有何帮助？

编辑：我使用while while循环而不是while＆amp;它起作用了

Answer 1

之前发生在我身上。数据库 id 是数字，函数是 string 。

这里的问题是你制作这段代码的时候：

String search_query = "SELECT * FROM "+ TABLE_NAME +" WHERE id=?";
Cursor cursor = db.rawQuery(search_query,new String []{id});

最终查询是...... "SELECT * FROM "+ TABLE_NAME +" WHERE id='1'"; 你真正想要的是"SELECT * FROM "+ TABLE_NAME +" WHERE id=1";

这是我的解决方案......

String search_query = "SELECT * FROM "+ TABLE_NAME +" WHERE id="+id;
Cursor cursor = db.rawQuery(search_query,null);

或

String search_query = "SELECT * FROM "+ TABLE_NAME +" WHERE cast(id as text)=?";
Cursor cursor = db.rawQuery(search_query,new String []{id});

使用自动生成的id android从表中选择*

1 个答案: