sql 时间段内没有的数据等于0

Posted 2020-08-11 真心面对

如何实现没有的时间段中使用0来填充？？

if object_id(\'[A]\') is not null drop table [A]
go 
create table [A]([日期] datetime,[金额] int)
insert [A]
select * from [A]
select \'2014-05-01\',100 union all
select \'2014-05-02\',200 union all
select \'2014-05-05\',300 union all
select \'2014-05-06\',200

declare @stdate smalldatetime,
        @eddate smalldatetime
select  @stdate=min([日期]),
        @eddate=max([日期]) from [A]
;
with sel as
(
 select @stdate as [date],1 as val
 union all
 select  dateadd(day,val,@stdate),val+1 as val from sel where val<=datediff(day,@stdate,@eddate)
)
select sel.[date] as [日期],sum(isnull(A.[金额],0)) as [金额] from sel
left join [A] on sel.[date]=[A].[日期] group by sel.[date]

解释一下：with这一步是关键，通过它使得“select dateadd(day,val,@stdate),val+1 as val from sel where val<=datediff(day,@stdate,@eddate)”一直在查询时间差

然后通过外链接关联