需要在我的代码中加入 if else 语句

Question

我试图在下面的代码中实现 if else 语句或 case 语句。我想使用这些语句之一（如果或案例）来查看我的 RT_Ch_Pres_PX1 值是否在特定的最小或最大规格范围内，如果它们高于或低于我想说如果我的 RT_Ch_Pres_PX1 低于我的最小值这么多然后显示该值并表示它是多少，并且与超过最大值相同。例如，如果我的 RT_Ch_Pres_PX1 值为 5，我想在 6 处使用我的最小值，在 10 处使用最大值。所以我的 Rt_Ch_pres_px1 值关闭了 1，所以我想显示这个并说这个值是 1 值。如果 RT_Ch_Pres_PX1 在最小值和最大值范围内，则什么也不做。请看下面的代码。

                    DECLARE @Result TABLE
            (
                        RT_DateTime datetime,
                        RT_Phase_Name varchar(30),
                        RT_PhaseChangeCount int,
                        RT_Phase_Type int,
                        RT_Ch_Pres_PX1 float           
            );
            /* Variables used to track changes to Phase Name */
            DECLARE @RT_DateTime datetime;
            DECLARE @RT_Phase_Name varchar(30);
            DECLARE @RT_PhaseChangeCount int;
            DECLARE @RT_Phase_Type int;
            DECLARE @RT_Ch_Pres_PX1 float;
            DECLARE @PhaseNameHold varchar(30);
            DECLARE @PhaseChangeCount int;
            SELECT @PhaseNameHold = ' ';
            SELECT @PhaseChangeCount = 0;
            SELECT @RT_PhaseChangeCount = 0;

            /* Declare a cursor for determining when Phases change */

            DECLARE ImportCursor CURSOR FAST_FORWARD FOR

            SELECT 
            CONVERT(datetime, dbo.CycleData.Date_Time) as TimeConvert, 
            [dbo].[LookupPhases].[Phase_Name],
            [dbo].[cycledata].[phase_type],
            [dbo].[cycledata].[Ch_Pres_PX1]

            FROM
             CycleData INNER JOIN
                                     CycleDataHeader ON CycleData.Unit_Number = CycleDataHeader.Unit_Number AND CycleData.Cycle_Counter_No = CycleDataHeader.Cycle_Counter_No INNER JOIN
                                     LookupPhases ON CycleData.Phase_Type = LookupPhases.Phase_Type INNER JOIN
                                     LookupEvent ON CycleData.Event_Type = LookupEvent.Event_Id LEFT OUTER JOIN
                                     LookupAlarm ON CycleData.Alarm_Type = LookupAlarm.Alarm_Id

              WHERE 
            [dbo].[CycleDataHeader].[Entered_Load_No1] = 'T14-0008'


            ORDER BY

            /* Appears to be the order that needs to be reported on */

            Cycle_Time
            -- dbo.CycleData.Unit_Number,

            -- TimeConvert;

            OPEN ImportCursor;

            FETCH NEXT FROM ImportCursor INTO @RT_DateTime, 
                                                @RT_Phase_Name,
                                                @RT_Phase_Type,
                                                @RT_Ch_Pres_PX1  
            WHILE @@FETCH_STATUS = 0
            BEGIN
            IF (@RT_Phase_Name <> @PhaseNameHold)   
                BEGIN
                                    SET @PhaseNameHold = @RT_Phase_Name;
                                    SET @RT_PhaseChangeCount = @RT_PhaseChangeCount + 1;
                                    END
                        INSERT INTO @Result VALUES(@RT_DateTime, @RT_Phase_Name,@RT_PhaseChangeCount,@RT_Phase_Type,@RT_Ch_Pres_PX1);           
                        FETCH NEXT FROM ImportCursor INTO @RT_DateTime, @RT_Phase_Name,@RT_Phase_Type,@RT_Ch_Pres_PX1;
            END
            CLOSE ImportCursor;
            DEALLOCATE ImportCursor;
            SELECT
                        RT_DateTime,
                        RT_Phase_Name,
                        RT_PhaseChangeCount,
                        RT_Phase_Type,
                        RT_Ch_Pres_PX1 


            FROM @Result;

Answer 1

这种情况会产生你想要的值：

case
  when RT_Ch_Pres_PX1 < some_min then RT_Ch_Pres_PX1 - some_min
  when RT_Ch_Pres_PX1 > some_max then RT_Ch_Pres_PX1 - some_max
  else 0
end

为下冲创造的价值是负的（我认为这是个好主意）。如果您希望它是正数，请翻转计算。