Question

提前谢谢。

我有table1和table2

表1

id   ||  date        || name_id   ||   value   
001  || 2017-12-01   || 212       || 23.091
002  || 2017-12-02   || 212       || 20.324
003  || 2017-12-03   || 212       || 21.765
004  || 2017-12-04   || 212       || 25.890
005  || 2017-12-01   || 497       || 23.291
006  || 2017-12-02   || 497       || 20.524
007  || 2017-12-03   || 497       || 21.705
008  || 2017-12-04   || 497       || 25.810
009  || 2017-11-01   || 242       || 23.492
010  || 2017-11-02   || 242       || 20.744
011  || 2017-11-03   || 242       || 21.076
012  || 2017-11-04   || 242       || 24.100
013  || 2017-10-01   || 197       || 23.376
014  || 2017-10-02   || 197       || 20.555
015  || 2017-10-03   || 197       || 21.965
016  || 2017-10-04   || 197       || 25.120

表2

id   ||  startup_date  || Name  
212  || 2017-11-31     || BVUNMI
497  || 2017-11-30     || OUKNGT
242  || 2017-10-26     || TYNBFD
197  || 2017-09-28     || WDRHBG

输出

id   ||  startup_date  || Name      ||   Avg_value
212  || 2017-11-31     || BVUNMI    ||   22.7675
497  || 2017-11-30     || OUKNGT    ||   23.291
242  || 2017-10-26     || TYNBFD    ||   22.353
197  || 2017-09-28     || WDRHBG    ||   22.754

这只是一个示例数据。我有1000条记录，无法弄清楚如何做到这一点。

逻辑是我需要计算从启动日期开始的第一次 30天的平均值。我必须取每个NAME_ID的平均值并创建，更新到table2中的新列。

我被困住了，不知道怎么走得更远。

感谢任何帮助。

Answer 1

使用子查询和dateadd

 select id,
        startup_date,
        Name,
        (
           select avg(value)
           from table1 t1
           where t1.name_id = t2.id and
                 date between t2.startup_date and dateadd(day, 30, t2.startup_date)
        ) Avg_value
 from table2 t2

或JOIN与GROUP BY

 select t2.id,
        t2.startup_date,
        t2.Name,
        avg(value) Avg_value
 from table2 t2
 join table1 t1 on t1.name_id = t2.id and
                   t1.date between t2.startup_date and dateadd(day, 30, t2.startup_date)
 group by t2.id,
          t2.startup_date,
          t2.Name

Answer 2

2017-11-31 - 不存在

所以我将其改为2017-11-30，这就是为什么我的结果与你的结果略有不同。遗憾的是，这样的查询可能会对大量数据产生不良影响。如果可能的话，我会建议对数据进行非规范化（将start_date添加到t1中）

SET DATEFORMAT dmy
declare @t1 table(id int , dt date, name_id int, value decimal(15,2))
declare @t2 table(id int , startup_date date, Name nvarchar(100))
insert into @t1(id,dt,name_id,value)
values
(001,convert(date,'2017-12-01',121),212    ,23.091),
(002,convert(date,'2017-12-02',121),212    ,20.324),
(003,convert(date,'2017-12-03',121),212    ,21.765),
(004,convert(date,'2017-12-04',121),212    ,25.890),
(005,convert(date,'2017-12-01',121),497    ,23.291),
(006,convert(date,'2017-12-02',121),497    ,20.524),
(007,convert(date,'2017-12-03',121),497    ,21.705),
(008,convert(date,'2017-12-04',121),497    ,25.810),
(009,convert(date,'2017-11-01',121),242    ,23.492),
(010,convert(date,'2017-11-02',121),242    ,20.744),
(011,convert(date,'2017-11-03',121),242    ,21.076),
(012,convert(date,'2017-11-04',121),242    ,24.100),
(013,convert(date,'2017-10-01',121),197    ,23.376),
(014,convert(date,'2017-10-02',121),197    ,20.555),
(015,convert(date,'2017-10-03',121),197    ,21.965),
(016,convert(date,'2017-10-04',121),197    ,25.120)

insert into @t2(id,startup_date,Name)
VALUES 
(212,convert(date,'2017-11-30',121),'BVUNMI'),
(497,convert(date,'2017-11-30',121),'OUKNGT'),
(242,convert(date,'2017-10-26',121),'TYNBFD'),
(197,convert(date,'2017-09-28',121),'WDRHBG')

select
avg(value)
from @t2 t2
inner join @t1 t1 on t2.id = t1.name_id and t1.dt < dateadd(d,30,t2.startup_date)
group by t1.name_id

Answer 3

试试这个：

select [t2].[Name], AVG([t1].[value]) from [table1] [t1] join [table2] [t2]
on [t1].[name_id] = [t2].[id] and [t1].[date] between [t2].[startup_date] and 
DATEADD(day, 30, [t2].[startup_date])
group by [t2].[Name]

如何使用函数计算平均值

3 个答案: