sql server - conversion failed when converting date /time from character string -

select [proc_id]     ,[contact_date_new]     ,[cpt_code_new]     ,[chargeable_yn_new]     ,cat.cdm_category     ,dateupdated     [dbo].cdm_audit_eap_ot]      @coldate between @start_date , @end_date 

after add new parameter @coldate, start getting above error.

@coldate has "contact_date_new" or "dateupdated". users choose either 1 depend on looking for.

if specify column directly, report work fine.

 contact_date_new between @start_date , @end_date  dateupdated between @start_date , @end_date 

the @coldate in query not treated column name, instead string type variable. when try compare values @startdate , @enddate fails. hence error. can create stored procedure follows suit need :-

create procedure [ssrsreport]  @start_date date, @end_date date, @coldate nvarchar(25)   begin set nocount on  declare @sql1 nvarchar(max)  if @coldate = 'contact_date_new'  begin set @sql1 =  'select [proc_id]     ,[contact_date_new]     ,[cpt_code_new]     ,[chargeable_yn_new]     ,cat.cdm_category     ,dateupdated     [dbo].cdm_audit_eap_ot]      contact_date_new between ''' + cast(convert(nvarchar(10),@start_date ,120) nvarchar(max)) +'''      , ''' + cast(convert(nvarchar(10),@end_date ,120) nvarchar(max)) + ''''     end      else if @coldate = 'dateupdated'      begin set @sql1 =  'select [proc_id]     ,[contact_date_new]     ,[cpt_code_new]     ,[chargeable_yn_new]     ,cat.cdm_category     ,dateupdated     [dbo].cdm_audit_eap_ot]      dateupdated between ''' + cast(convert(nvarchar(10),@start_date ,120) nvarchar(max)) +'''      , ''' + cast(convert(nvarchar(10),@end_date ,120) nvarchar(max)) + ''''     end      print @sql1     exec sp_executesql @sql1  end