Incorrect next near when use iif with set in sql Servr

When I use a statement and set in same query, we get

Incorrect syntax near ”

    DECLARE @Enter int
    DECLARE @Month INT
    DECLARE @year INT 
    DECLARE @Delayed INT = NULL
    DECLARE @NextMonth INT =  null
    DECLARE @AfterNextMonth INT = NULL
    DECLARE @beyond INT = null


        SELECT @Enter = MONTH(GETDATE()), @year = YEAR(GETDATE())
        SELECT *
            SET @Delayed = IIF(MONTH(ExpectedDeliveryDate) <  MONTH(GETDATE()) AND YEAR(ExpectedDeliveryDate) < YEAR(GETDATE()), OpemAmount,'Null') 
            SET @Month = IIF(MONTH(ExpectedDeliveryDate) =  MONTH(GETDATE()), OpemAmount,'Null') 
            SET @NextMonth = IIF(MONTH(ExpectedDeliveryDate) =  MONTH(GETDATE()) + 1, OpemAmount,'Null')  
            SET @AfterNextMonth = IIF(MONTH(ExpectedDeliveryDate) =  MONTH(GETDATE()) +2, OpemAmount,'Null')  
            SET @beyond = IIF(MONTH(ExpectedDeliveryDate) >  MONTH(GETDATE()) AND YEAR(ExpectedDeliveryDate) > YEAR(GETDATE()) OR 
                             MONTH(ExpectedDeliveryDate) = Null , OpemAmount,'Null')  

            @Delayed AS Delayed, @Month AS '@Enter', @NextMonth AS '@NextMonth', @AfterNextMonth AS '@AfterNextMonth' , @beyond AS '@beyond'   
     FROM dbo.vwOpenSalesOrders 

we declare 5 variables, what would to write when we get error in @Delayed after finisshed the statement.

Answer

SELECT *,
     IIF(MONTH(ExpectedDeliveryDate) <  MONTH(GETDATE()) AND YEAR(ExpectedDeliveryDate) < YEAR(GETDATE()), 'OpemAmount','Null') AS Delayed,
    IIF(MONTH(ExpectedDeliveryDate) =  MONTH(GETDATE()), 'OpemAmount','Null') AS Months,
   IIF(MONTH(ExpectedDeliveryDate) =  MONTH(GETDATE()) + 1,'OpemAmount','Null')  AS NextMonth,
    IIF(MONTH(ExpectedDeliveryDate) =  MONTH(GETDATE()) +2, 'OpemAmount','Null')  AS AfterNextMonth,
     IIF(MONTH(ExpectedDeliveryDate) >  MONTH(GETDATE()) AND YEAR(ExpectedDeliveryDate) >= YEAR(GETDATE()) OR 
                     MONTH(ExpectedDeliveryDate) = Null , 'OpemAmount','Null') AS  beyond 

FROM dbo.vwOpenSalesOrders