SAP Hana - SQL - 計算不含遞歸函數的同一個表上的列

Question

我有以下簡單的表格， 40k條目：

|date|consum| 

基於此表，我想計算一些新的列。最後，這個表應該是這樣的：

|date|consum|row|row_relativ|min|max|upper|lower| 

不幸的是，SAP HANA數據庫不支持遞歸表的語句...

下面是計算規則：

1. 行= row_number() over(order by dates)
2. row_relative = row*35040/32768
3. 分鐘= floor(row_relative)
4. 最大= ceil(row_relative)
5. 分鐘=選擇該行中的消費與最小值
6. 最大=選擇該行中的消費與最大值

目前我有一個存儲precedure與5個變量。在每個變量中，我計算我新的coulmn。這是非常非常骯髒的...我怎樣才能讓它不同？我不能使用遞歸函數...：/

這裏是我的SQL片段......玩得開心=）

var1 = select *, row_number() over(order by dates) as row from XYZ order by dates limit 34944; 
var2 = select *, (row * 34944/32768) as row_relative from :var1; 
var3 = select *, floor(row_relative) as min, ceil(row_relative) as max from :var2; 

var4 = select 
    p.*, 
    (select consumfrom :var3 where row = p.min) as lower, 
    (select consumfrom :var3 where row = p.max) as upper 
from :var3 p; 

var5 = select 
    p.*, 
    (p.lower* (1-p.row_relative+p.min)+p.upper * (p.row_relativ - p.min)) as new_consum 
from :var4 p; 

Answer 1

您可以在SQLScript BTW使用以下CTE公共表表達式，它是非常有趣的是幾乎相同的SQL Server CTE語法相匹配的SAP HANA SQLScript語法:)

with cte as (
select 
    date, 
    consum, 
    row_number() over (order by date) as row 
from rawdata 
) 
select 
    date, 
    consum, 
    row, 
    row * 35040/32768 as row_relative, 
    floor((row * 35040/32768)) as min, 
    ceil((row * 35040/32768)) as max, 
    (select cte2.consum from cte cte2 where row = floor((cte.row * 35040/32768))) as min2, 
    (select cte2.consum from cte cte2 where row = ceil((cte.row * 35040/32768))) as max2 
from cte