declare @sqlExpr varchar(max)='';
declare @allVersion varchar(4000)='';
declare @allJoin varchar(4000)='';

SELECT *  INTO #tt
FROM (values('st1','val1',1),('st2','val2',1),('st3','val3',1), ('st1',	'val4',	2), ('st3','val5',2),('st3','val6',3)) t(stand,value,version);

select @allVersion=(select 
  STRING_AGG ('isnull(c'+ version +'.value,''-'') as ['+version+']',',') 
   WITHIN GROUP ( ORDER BY version) 
   FROM (select distinct trim(cast(version as char)) as version from #tt) t)
select @allJoin=(select 
  STRING_AGG ( ' left join #tt as c'+ version
              +' on c'+version+'.stand=st.stand'
              +' and c'+version+'.version='+version
              ,char(13)) 
   WITHIN GROUP ( ORDER BY version) 
   FROM (select distinct trim(cast(version as char)) as version from #tt) t)

select @sqlExpr='SELECT st.stand AS stand, '+@allVersion 
+' FROM  (select stand from #tt group by stand) st '+char(13)
+@allJoin

execute (@sqlExpr)