Question

If I select from a table group by the month, day, year, it only returns rows with records and leaves out combinations without any records, making it appear at a glance that every day or month has activity, you have to look at the date column actively for gaps. How can I get a row for every day/month/year, even when no data is present, in T-SQL?

Answer 1

My developer got back to me with this code, underscores converted to dashes because StackOverflow was mangling underscores — no numbers table required. Our example is complicated a bit by a join to another table, but maybe the code example will help someone someday.

declare @career-fair-id int  select @career-fair-id = 125  create table #data ([date] datetime null, [cumulative] int null)   declare @event-date datetime, @current-process-date datetime, @day-count int  select @event-date = (select careerfairdate from tbl-career-fair where careerfairid = @career-fair-id)  select @current-process-date = dateadd(day, -90, @event-date)       while @event-date <> @current-process-date      begin      select @current-process-date = dateadd(day, 1, @current-process-date)      select @day-count = (select count(*) from tbl-career-fair-junction where attendanceregister <= @current-process-date and careerfairid = @career-fair-id)          if @current-process-date <= getdate()          insert into #data ([date], [cumulative]) values(@current-process-date, @day-count)      end       select * from #data      drop table #data