sql server 当前时间属于哪个区间问题

 declare @currentDateTime datetime;
          declare @currentHour float;
          declare @currentMinute float;
          declare @ElectricityUnitPrice  numeric(18, 2); --电单价
          
          declare @Clock0 datetime;
          declare @Clock8 datetime;
          declare @Clock9 datetime;
          declare @Clock12 datetime;
          declare @Clock19 datetime;
          declare @Clock22 datetime;
          declare @Clock24 datetime;
         
          set @currentDateTime=GETDATE();
          set @currentHour=DATEPART(hour,@currentDateTime)  --获取当前时间小时部分
          set @currentMinute=DATEPART(MINUTE,@currentDateTime)

             
          set @Clock0=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 00:00:000‘);
          set @Clock8=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 8:00:000‘);
          set @Clock9=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 9:00:000‘);
          set @Clock12=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 12:00:000‘);
          set @Clock19=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 19:00:000‘);
          set @Clock22=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 22:00:000‘);
          set @Clock24=Convert(datetime,convert(varchar(10),@currentDateTime,120)+‘ 23:59:000‘);
      
          if (@currentHour=0) and (@currentMinute=0)  --小时、分钟都为零，即为24点，平峰结束时刻
            begin
               set @ElectricityUnitPrice=1.0; --平峰电价
            end
         
         else --不是24点
           begin
            if(@currentHour!=0) and  (@currentMinute=0)  --xxx点整
             begin
               set @currentDateTime=dateadd(minute,-30,@currentDateTime); --临界点的区间等于前半个小时所在的区间
             end
            
              if (@Clock0<@currentHour and @currentHour<@Clock8)
                   begin
                     set @ElectricityUnitPrice=0.8; --谷峰电价
                   end
             else if(@Clock8<@currentHour and @currentHour<@Clock9) 
                 or (@Clock12<@currentHour and @currentHour<@Clock19)
                 or (@Clock22<@currentHour and @currentHour<@Clock24)
                 begin
                    set @ElectricityUnitPrice=1; --平峰电价
                 end
             else if(@Clock9<@currentHour and @currentHour<@Clock12) 
                   or(@Clock19<@currentHour and @currentHour<@Clock22)  
                 begin
                   set @ElectricityUnitPrice=1.5; --高峰电价
                 end
             else
               begin
                 --脚本无错的话，不会执行到这一步
                 set @ElectricityUnitPrice=-1; 
               end
          end