如何使用SQL语句在指定的日期获取汇总的总和

Question

I am trying to generate sums of transactions which is contained in a SQL Server table using this script:

Select Category,Sum(Items) as CategoryTotals 
from TransactionsTable  
where TransDate <=ReportingDate
Group By Category

I also have a list of dates for which this information is required as:

Select ReportingDates From AllMyDatesTable

Can anyone assist me with how I can structure a query to join the two queries to get a list of CategoryTotals at Specified dates similar to

Select ReportingDates,CategoryTotals from (My Two Tables)?

Any help appreciated

Answer 1

Something like this? If you want to show dates even if no transaction is found go for left join instead of inner join

Select d.ReportingDates,t.Category,Sum(d.Items)
  from AllMyDatesTable d inner join TransactionsTable t 
    on d.ReportingDates = t.TransDate 
   and d.TransDate <= ReportingDate
 group by d.ReportingDates,t.Category