declare @sql as nvarchar(max) execute sp_executesql @sql

declare @sql as nvarchar(max)
set @sql =
N'INSERT INTO [dbo].[PBB] ('+@Groupby+',[iNumber],[TimeDate_Start],[TimeDate_End])
SELECT distinct '+@Groupby+','+quotename(@MonthCalType,'''')+' as iNumber,'+quotename(@TimeDate_Start,'''')+' as TimeDate_Start,'+quotename(@TimeDate_End,'''')+' as TimeDate_End
 FROM #temp1 where timedate>='+quotename(@TimeDate_Start,'''')+' and timedate<='+quotename(@timedate_end,'''')
execute sp_executesql @sql