create table totalday
(swsb varchar(50), swxb varchar(50), xwsb varchar(50), xwxb varchar(50), wssb varchar(50), 
 wsxb varchar(50), kqkh varchar(50), rq varchar(50))

insert totalday
select '1', '2', '3', '4', '5', '6', '001', '2007-10-20'
GO

create Procedure Sp_Uptotalday
@sssj varchar(8),
@time varchar(50) output,
@rq varchar(10),
@kqkh varchar(10)
AS
Begin
    Declare @sql nvarchar(100)
    declare @oldtime varchar(50)
    set @sql = 'SELECT @oldtime = ' + @sssj + ' from totalday where rq = ''' + @rq + ''' and kqkh=''' + @kqkh + ''''
    exec sp_executesql @sql, N'@oldtime varchar(50) OUTPUT', @oldtime OUTPUT
    set @time = @oldtime
END

GO

declare @time varchar(50)
exec Sp_Uptotalday 'swsb', @time OUTPUT, '2007-10-20', '001'
select @time

GO

drop table totalday
drop procedure Sp_Uptotalday