SQL在SQL中没有关系时将数据创建为表答案

【问题标题】：SQL to create data as table when there is no relation in SQLSQL在SQL中没有关系时将数据创建为表
【发布时间】：2021-09-14 14:00:08
【问题描述】：

我有以下表格

表 1 我有费率

表 2 我有日期

表 3 我有数据显示适用于 start 和 end

之间的费率价格

我想用 SQL 查询创建 表 4，其中我有每个

汇率（来自表 1）+ 每个日期（来自表 2）+ 如果该日期存在于开始价格和结束价格之间，否则 0 显示如下表 4

我不知道如何在 SQL 查询中实现它，因为我是 SQL 新手，以及如果表之间没有关系如何链接

表 1

Rate	ID
ConfD1	46
ConfD2	47

表 2

Dates
15-09-2018
16-09-2018
17-09-2021
18-09-2021
19-02-2022

表 3

Rate	ID	startdate	enddate	price
ConfD1	46	01-01-2021	31-10-2021	111
ConfD1	46	01-11-2021	01-03-2022	222
ConfD2	47	01-01-2021	31-10-2021	333
ConfD2	47	01-11-2021	01-03-2022	444
ConfD3	48	01-01-2021	31-10-2021	555
ConfD3	48	01-11-2021	01-03-2022	666

表 4

Rate	date	price
ConfD1	15-09-2018	0
ConfD1	16-09-2018	0
ConfD1	17-09-2021	111
ConfD1	18-09-2021	111
ConfD1	19-02-2022	222
ConfD2	15-09-2018	0
ConfD2	16-09-2018	0
ConfD2	17-09-2021	333
ConfD2	18-09-2021	333
ConfD2	19-02-2022	444

【问题讨论】：

confD2的id是47，为什么在表2中显示为46？？
@RobertoHernandez 复制粘贴 :) ，现已更新

标签： sql sql-server

【解决方案1】：

不错的工作共享数据和所需的输出。如果下次您将数据变为可消耗的，那会更容易。像这样。

create table Table1
(
    Rate varchar(10)
    , ID int
)

insert Table1
select 'ConfD1', 46 union all
select 'ConfD2', 47

set dateformat dmy

create table Table2
(
    Dates date
)

insert Table2
select '15-09-2018' union all
select '16-09-2018' union all
select '17-09-2021' union all
select '18-09-2021' union all
select '19-02-2022'

create table Table3
(
    Rate varchar(10)
    , ID int
    , startdate date
    , enddate date
    , price int
)

insert Table3
select 'ConfD1', 46, '01-01-2021', '31-10-2021', 111 union all
select 'ConfD1', 46, '01-11-2021', '01-03-2022', 222 union all
select 'ConfD2', 46, '01-01-2021', '31-10-2021', 333 union all
select 'ConfD2', 46, '01-11-2021', '01-03-2022', 444 union all
select 'ConfD3', 46, '01-01-2021', '31-10-2021', 555 union all
select 'ConfD3', 46, '01-11-2021', '01-03-2022', 666

此查询将返回您要查找的数据。

select t1.Rate
    , t2.Dates
    , price = coalesce(t3.price, 0)
from Table1 t1
cross join Table2 t2
left join Table3 t3 on t3.startdate <= t2.Dates 
                    and t3.enddate >= t2.Dates 
                    and t3.rate = t1.rate

【讨论】：

【解决方案2】：

with dates ( coddate ) as 
(  select convert(datetime , '15/09/2018' , 103) union all
   select convert(datetime , '16/09/2018' , 103) union all
   select convert(datetime , '17/09/2021' , 103) union all
   select convert(datetime , '18/09/2021' , 103) union all
   select convert(datetime , '19/02/2021' , 103) 
) ,
rates  ( rate, id ) as
( 
select 'ConfD1' , 46 union all 
select 'ConfD2' , 47  
), 
rateprices ( Rate , Id, Startdate , EndDate, price ) 
as
(  select 'ConfD1' , 46 , convert(datetime , '01/01/2021' , 103) , convert(datetime , '31/10/2021' , 103 ), 111 union all
   select 'ConfD1' , 46 , convert(datetime , '01/01/2021' , 103) , convert(datetime , '01/03/2022' , 103 ), 222 union all
   select 'ConfD2' , 47 , convert(datetime , '01/01/2021' , 103) , convert(datetime , '31/10/2021' , 103 ), 333 union all
   select 'ConfD2' , 47 , convert(datetime , '01/01/2021' , 103) , convert(datetime , '01/03/2022' , 103 ), 444 union all
   select 'ConfD3' , 48 , convert(datetime , '01/01/2021' , 103) , convert(datetime , '31/10/2021' , 103 ), 555 union all 
   select 'ConfD3' , 48 , convert(datetime , '01/01/2021' , 103) , convert(datetime , '01/03/2022' , 103 ), 666 
), 
rates_and_dates ( rate , id , coddate ) 
as 
( select a.rate , a.id , b.coddate from rates a cross join dates b
), 
result ( rate, id, coddate, price )
as
(
select a.rate , a.id , a.coddate , price = coalesce(b.price, 0)
from rates_and_dates a inner join rates c 
  on a.rate=c.rate  
left join rateprices b 
  on a.rate=b.rate and b.startdate <= a.coddate and b.enddate >= a.coddate 
) 
select rate, coddate, price  from result 
order by 2, 1

db<>fiddle

【讨论】：