SSRs parameters is empty report not running

Question

I am using reportbuilder to build a report, using a subreport inside report. For different dates I am some ad_site is empty, data from query is not coming. data set query is

declare @count int

select count(distinct(computer_name)) as machine_count
  , ad_site as ad_site,ad_zone as ad_zone
from SCCM_PCrefreshdata
where ad_site is not null and snapshotdate like @startdate
group by ad_site,ad_zone

If I am entering date '2019-03-01' there is no data in table and same I am using ad_site for parameter in subreport

I HAVE kept parameter as allow nulls

Even after that if I run report and enter start date, for which data is not existing it gives following error

Answer 1

如果您希望保留参数以允许为空，则您的数据集查询也应引用此概念，即：其中ad_site为null且快照日期为@startdate