Qlikview - 填充缺少日期并查看给定ID的前一个日期值

Question

`
当前数据集 - 具有日期，ID和值

Expected Result

Date    | ID | Value
--------------------
2/4/17  | 3  |  4.4
2/4/17  | 9  |  6.2
2/5/17  | 3  |  4.4
2/5/17  | 9  |  6.2
2/6/17  | 3  |  4.4
2/6/17  | 9  |  6.2
2/7/17  | 3  |  4.4
2/7/17  | 9  |  6.2
2/8/17  | 3  |  4.4
2/8/17  | 9  |  6.2
2/9/17  | 3  |  4.7
2/9/17  | 4  |  7.4
2/9/17  | 9  |  9.4
2/10/17 | 3  |  4.7
2/10/17 | 4  |  7.4
2/10/17 | 9  |  9.4
2/11/17 | 3  |  9.7
2/11/17 | 7  |  12.4

`预期结果 - 我想填充缺少的日期并查看每个ID及其值，直到下一个日期。

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Answer 1

在遇到这种情况时，我通常使用类似下面的脚本。

基本上即时＃＆＃34;填充＆＃34;缺少日期但交叉连接所有可能的日期将显示所有可能的ID值，然后检查以前的Value值。

请注意，交叉加入会生成大表格 - 例如，有10个Dates和10个ID会产生包含100行，20 Dates和20 ID的表格 - 400行等，如果我们有太多的历史和太多的ID ......事情会很快变得令人讨厌（密切关注内存消耗）

// Load temp data
// just to be sure convert the original Date field to date
Data_Temp:
Load
  date(date#(Date, 'M/D/YY')) as Date,
  ID,
  Value
;
Load * Inline [
Date    , ID , Value
2/4/17  , 3  ,  4.4
2/4/17  , 9  ,  6.2
2/9/17  , 3  ,  4.7
2/9/17  , 4  ,  7.4
2/9/17  , 9  ,  9.4
2/11/17 , 3  ,  9.7
2/11/17 , 7  ,  12.4
];


// Autogenerate all dates
// between min and max date
// from Data_Temp table
Dates:
Load
    Date(MinDate+IterNo()-1) as Date
While 
    MinDate+IterNo()-1<=MaxDate;
;
Load
     Min(Date) as MinDate,
     Max(Date) as MaxDate
Resident 
    Data_Temp
;

// Join the distinct ID to the Dates table
// the result table will be cross join
// all dates for all IDs
join

Load
  distinct
  ID
Resident
  Data_Temp
;  


// join the "cross table" to the data table
// The result table will have the original data
// plus all missing dates per ID
join (Data_Temp)

Load * Resident Dates;

// we dont need this anymore
Drop Table Dates;

// This is the fun part ...
// 1. load the Data_Temp table and order it by ID and Date
// 2. for each row:
// 2.1. check if the current ID value is not equal to the previous row ID value
//      if "yes" (new ID set) get the current Value
//      if "no" check if the current value is > 0
//          if "yes" keep the current value
//          if "no" get the peek value of the current field (NewValue)
Data:
// // Uncomment the script section below
// // if we need to exclude the rows with NewValue = null

//Load
//  *
//where
//  NewValue > 0
//; 
Load
    ID,
    Date, 
    Value,
    if( ID <> peek(ID), Value,
      if( Value > 0, Value, peek(NewValue) ) 
    ) as NewValue
Resident
    Data_Temp
Order By
    ID,
    Date    
;

// we dont need this anymore
Drop Table Data_Temp;

// // At this point we can drop the old Value field
// // and rename the NewValue to Value ... if needed

//Drop Field Value;
//Rename Field NewValue to Value;

运行脚本后，结果就是：

您可以下载示例QV文件here