如何获得空值的以前值

Question

我的表中有以下数据。

| Id | FeeModeId |Name  | Amount| 
    --------------------------------------------- 
    | 1 | NULL  | NULL  | 20 | 
    | 2 | 1   | Quarter-1 | 5000 | 
    | 3 | NULL  | NULL  | 2000 |  
    | 4 | 2   | Quarter-2 | 8000 | 
    | 5 | NULL  | NULL  | 5000 | 
    | 6 | NULL  | NULL  | 2000 | 
    | 7 | 3   | Quarter-3 | 6000 | 
    | 8 | NULL  | NULL  | 4000 | 

如何写这样的查询得到下面的输出...

| Id | FeeModeId |Name  | Amount| 
    --------------------------------------------- 
    | 1 | NULL  | NULL  | 20 | 
    | 2 | 1   | Quarter-1 | 5000 | 
    | 3 | 1   | Quarter-1 | 2000 |  
    | 4 | 2   | Quarter-2 | 8000 | 
    | 5 | 2   | Quarter-2 | 5000 | 
    | 6 | 2   | Quarter-2 | 2000 | 
    | 7 | 3   | Quarter-3 | 6000 | 
    | 8 | 3   | Quarter-3 | 4000 | 

Answer 1

请尝试：

select 
    a.ID, 
    ISNULL(a.FeeModeId, x.FeeModeId) FeeModeId, 
    ISNULL(a.Name, x.Name) Name, 
    a.Amount 
from tbl a 
outer apply 
(select top 1 FeeModeId, Name 
    from tbl b 
    where b.ID<a.ID and 
     b.Amount is not null and 
     b.FeeModeId is not null and 
     a.FeeModeId is null order by ID desc)x 

OR

select 
    ID, 
    ISNULL(FeeModeId, bFeeModeId) FeeModeId, 
    ISNULL(Name, bName) Name, 
    Amount 
From(
    select 
     a.ID , a.FeeModeId, a.Name, a.Amount, 
     b.ID bID, b.FeeModeId bFeeModeId, b.Name bName, 
     MAX(b.FeeModeId) over (partition by a.ID) mx 
    from tbl a left join tbl b on b.ID<a.ID 
    and b.FeeModeId is not null 
)x 
where bFeeModeId=mx or mx is null 

Answer 2

试试这个 -

SELECT Id, 
     CASE 
     WHEN Feemodeid IS NOT NULL THEN 
      Feemodeid 
     ELSE 
      (SELECT Feemodeid 
      FROM Table_Name t_2 
      WHERE t_2.Id = (SELECT MAX(Id) 
           FROM Table_Name t_3 
          WHERE t_3.Id < t_1.Id 
           AND Feemodeid IS NOT NULL)) 
     END Feemodeid, 
     CASE 
     WHEN NAME IS NOT NULL THEN 
      NAME 
     ELSE 
      (SELECT NAME 
      FROM Table_Name t_2 
      WHERE t_2.Id = (SELECT MAX(Id) 
           FROM Table_Name t_3 
          WHERE t_3.Id < t_1.Id 
           AND NAME IS NOT NULL)) 
     END NAME, 
     Amount 
    FROM Table_Name t_1 

Answer 3

SELECT 
    T.ID, 
    ISNULL(T.FeeModeId, 
    (SELECT TOP 1 FeeModeId 
     FROM TableName AS T1 
     WHERE ID < T.ID AND FeeModeId IS NOT NULL 
     ORDER BY ID DESC)) AS FeeModeId, 
    ISNULL(Name, 
    (SELECT TOP 1 Name 
    FROM TableName 
    WHERE ID < T.ID AND Name IS NOT NULL 
    ORDER BY ID DESC)) AS Name, 
    T.Amount 
FROM 
    TableName AS T 

Answer 4

既然你的SQL Server 2012上...在这里是一个使用它的版本。它可能比其他解决方案更快，但您必须对您的数据进行测试。

sum() over()会做的Id有序运行总和增加1当有在列中的值，并保持当前值null值。然后使用计算的运行总和将结果分区为first_value() over()。第一个值由Id按运行总和生成的每个“组”行具有您想要的值。

select T.Id, 
     first_value(T.FeeModeId) 
      over(partition by T.NF 
       order by T.Id 
       rows between unbounded preceding and current row) as FeeModeId, 
     first_value(T.Name)  
      over(partition by T.NS 
       order by T.Id 
       rows between unbounded preceding and current row) as Name, 
     T.Amount 
from (
    select Id, 
      FeeModeId, 
      Name, 
      Amount, 
      sum(case when FeeModeId is null then 0 else 1 end) 
       over(order by Id) as NF, 
      sum(case when Name is null then 0 else 1 end) 
       over(order by Id) as NS 
    from YourTable 
    ) as T 

SQL Fiddle

的东西，将前期工作的SQL Server 2012：

select T1.Id, 
     T3.FeeModeId, 
     T2.Name, 
     T1.Amount 
from YourTable as T1 
    outer apply (select top(1) Name 
       from YourTable as T2 
       where T1.Id >= T2.Id and 
        T2.Name is not null 
       order by T2.Id desc) as T2 
    outer apply (select top(1) FeeModeId 
       from YourTable as T3 
       where T1.Id >= T3.Id and 
        T3.FeeModeId is not null 
       order by T3.Id desc) as T3 

SQL Fiddle

Answer 5

id name 
1 toto 
2 NULL 
3 NULL 
4 titi 
5 NULL 
6 NULL 
7 tutu 
8 NULL 
9 NULL 


SELECT 
     id_table 
     ,name 
FROM 
     (
      SELECT 
        T_01.id AS 'id_table' 
        ,max(T_02.id) AS 'id_name' 
      FROM 
        names AS T_01 
        cross join 
        (
          SELECT 
           id 
           ,name 
          FROM 
           names 
          WHERE 
           name IS NOT NULL 
        ) AS T_02 
      WHERE 
        T_02.id <= T_01.id 
      GROUP BY 
        T_01.id 
     ) AS tt02 
     left join names 
     ON names.id = tt02.id_name 


id_table name 
1   toto 
2   toto 
3   toto 
4   titi 
5   titi 
6   titi 
7   tutu 
8   tutu 
9   tutu