How to prevent update to category only by part id when it be blank or NULL on inputdata table?

Transact-SQL
,
1

I work on sql server 2012 I face issue I need to do update data found on table #DataUpdated based on part id exist on table #inputdata .

my issue on category on inputdata will update #dataupdated table when it have value only and not equal NULL
OR Blank .
so I need to update full row by parts id .

my issue i can't avoid update to data inputdata by partid where category on input data is null or blank
so how to do that

update d set d.category=i.category from #DataUpdated d
inner join #inputdata i on i.partid=d.partid

 create table #inputdata
 (
 PartId  int,
 category nvarchar(50),
 NameGeneration  nvarchar(50)
 )
 insert into #inputdata(PartId,category,NameGeneration)
 values
 (2020,NULL,'v5070'),
 (2030, '','v5080'),
 (2050,'Iron2','v5090'),
 (2090,'Plaster2','v8000')
    
 create table #DataUpdated
 (
 PartId  int,
 category nvarchar(50),
 NameGeneration  nvarchar(50)
 )
 insert into #DataUpdated(PartId,category,NameGeneration)
 values
 (2020,'Plastic','v5050'),
 (2030,'Alomental','v5050'),
 (2050,'Iron','v5050'),
 (2090,'Plaster','v9000')
    
    
    
 result expected

SELECT * FROM #DataUpdated
PartId category NameGeneration
2020 Plastic v5070
2030 Alomental v5080
2050 Iron2 v5090
2090 Plaster2 v8000
2

You can do the update couple of different ways. For instance,

UPDATE du SET
    du.category = COALESCE(i.category,du.category),
    du.NameGeneration = COALESCE(i.NameGeneration, du.NameGeneration)
FROM
    #DataUpdated AS du
    INNER JOIN #inputdata AS i ON
        i.PartId = du.PartId;