如何从开始日期创建日期范围行和Prestodb SQL中的数字？

Question

我在prestodb中有这种表格，其中包含start_date字段和增量计数器。

| num | start_date | val |
|-----|------------|-----|
| 2   | 2017-03-01 | 100 |
| 3   | 2017-03-05 | 233 |

如何使用presto sql将其转换为此类表？

| date       | val |
|------------|-----|
| 2017-03-01 | 100 |
| 2017-03-02 | 100 |
| 2017-03-05 | 233 |
| 2017-03-06 | 233 |
| 2017-03-07 | 233 |

谢谢！

Answer 1

select  date_add ('day',s.n,t.start_date) as date
       ,t.val 

from    mytable t 
        cross join unnest(sequence(0,num-1)) s (n)
;

    date    | val
------------+-----
 2017-03-01 | 100
 2017-03-02 | 100
 2017-03-05 | 233
 2017-03-06 | 233
 2017-03-07 | 233

Answer 2

试试Sql Server

Declare @s_id int = 1
;WITH dates AS 
(
    SELECT start_date as Date,@s_id as times,num as value,val
    from  @t 
    UNION ALL
    SELECT DATEADD(d,1,[Date]),times+1 as times,value,val
    FROM dates 
    WHERE times  < value
)

select Date,val from dates
order by val,date

请注意，可以使用...

创建此语句的测试表

declare @t ( num int,start_date date,val int)
insert into @t values (2,'2017-03-01',100)
insert into @t values (3,'2017-03-05',233)

在针对您的表测试主要语句时，请将主语句中的@t替换为您的表名。

下图显示了针对测试表运行主语句的结果......