Question

所以我有大约160 000个条目的数据集，它们是计算机生成的，并且多年来发生了错误。

让我们说表有以下几列：

- EntryID (auto int)
- FruitNumber
- JuiceNumber
- CandyNumber
- Date

现在重要的是，FruitNumber, JuiceNumber,CandyNumber的每个组合在它们之间的时间少于12个月时都是唯一的。

这意味着所有这些精确组合只能在12个月内存在一次。现在，我需要将此数据集迁移到新的数据模型中，为此，我需要删除重复的记录（但保留其中的1条记录），我在Queries上进行了很多尝试，但找不到解决方案。

Answer 1

尝试使用cte：

 private ActionBar toolbar;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    toolbar = getSupportActionBar();
    toolbar.setTitle("Home");
    loadFragment(new home());

    BottomNavigationView navigation = (BottomNavigationView)findViewById(R.id.navigation);
    navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);

}

private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
        = new BottomNavigationView.OnNavigationItemSelectedListener() {
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
        Fragment fragment;
        switch (menuItem.getItemId()){

            case R.id.navigation_home:
                toolbar.setTitle("Home");
                fragment = new home();
                loadFragment(fragment);
                return true;

            case R.id.navigation_dashboard:
                toolbar.setTitle("Dashboard");
                fragment = new Dashboard();
                loadFragment(fragment);
                return true;

            case R.id.navigation_notifications:
                toolbar.setTitle("Notifications");
                fragment = new Notification();
                loadFragment(fragment);
                return true;

            case R.id.navigation_profile:
                toolbar.setTitle("Profile");
                fragment = new Profile();
                loadFragment(fragment);
                return true;
        }

        return false;
    }
};

private void loadFragment(Fragment fragment){

    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.frame_container, fragment);
    transaction.addToBackStack(null);
    transaction.commit();
}

以及示例数据：

private OnFragmentInteractionListener mListener;

Button AskForHelp, Drafts, LogOut, Settings;

View view;

public Dashboard() {
    // Required empty public constructor
}

public static Dashboard newInstance(String param1, String param2) {
    Dashboard fragment = new Dashboard();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    view = inflater.inflate(R.layout.fragment_dashboard, container,false);

    AskForHelp = (Button)view.findViewById(R.id.askHelp);
    AskForHelp.setOnClickListener(this);

    Drafts = (Button)view.findViewById(R.id.drafts);
    Drafts.setOnClickListener(this);

    LogOut = (Button)view.findViewById(R.id.logOut);
    LogOut.setOnClickListener(this);

    Settings = (Button)view.findViewById(R.id.settings);
    Settings.setOnClickListener(this);

    return view;

}

public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction(uri);
    }
}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}

@Override
public void onClick(View v) {

    switch (v.getId()){

        case R.id.askHelp:
            Intent intent = new Intent(getContext(), Questions.class);
            startActivity(intent);
            break;

        case R.id.drafts:
            Toast.makeText(getContext(),"Function not enabled", Toast.LENGTH_SHORT).show();
            break;

        case R.id.logOut:
            Toast.makeText(getContext(),"Function not enabled", Toast.LENGTH_SHORT).show();
            break;

        case R.id.settings:
            Toast.makeText(getContext(),"Function not enabled", Toast.LENGTH_SHORT).show();
            break;
    }

}

public interface OnFragmentInteractionListener {
    void onFragmentInteraction(Uri uri);
}

和输出：

;WITH cte AS 
(
SELECT 
  ft.EntryID
, ft.FruitNumber
, ft.JuiceNumber
, ft.CandyNumber
, ft.Date
, ROW_NUMBER() OVER (PARTITION BY ft.FruitNumber, ft.JuiceNumber, ft.CandyNumber 
     ORDER BY ft.FruitNumber) RN
, DENSE_RANK() OVER (ORDER BY ft.FruitNumber, ft.JuiceNumber, ft.CandyNumber) 
     AS Partitionid
, COUNT(1) OVER (PARTITION BY ft.FruitNumber, ft.JuiceNumber, ft.CandyNumber 
     ORDER BY ft.FruitNumber) as PartitionCNT
FROM FooTable ft
)

SELECT 
t1.* 
, DATEDIFF(DAY, t.Date, t1.Date) DATEDiff
FROM 
cte t 
INNER JOIN cte t1 
    ON t1.FruitNumber = t.FruitNumber
        AND  t1.JuiceNumber = t.JuiceNumber
        AND  t1.CandyNumber = t.CandyNumber
        AND DATEDIFF(DAY, t.Date, t1.Date)>= 365
WHERE t.PartitionCNT > 1

Answer 2

如果错误只是偶然的，那么这很可能会起作用：

select t.*
from (select t.*,
             lag(date) over (partition by FruitNumber, JuiceNumber, CandyNumber) as prev_date
      from t
     ) t
where prev_date is null or prev_date < dateadd(year, -1, date);

这不是一般的解决方案-尽管您可以多次运行此查询。特别是，这仅在一年内最多重复一次时有效。

不幸的是，常规解决方案需要递归CTE。例如，如果您每个月都有一条记录，那么弄清楚如何保留“一月”记录就很棘手。

在给定日期删除重复的行组合

2 个答案: