declare @t table(id float)
insert @t select 1
insert @t select 1.23
insert @t select 1.258
select case when cast(ID as float) > cast(ID as int) then cast(ID as float) 
            else cast(ID as int) end ID
from @t
/*
ID
----------------------
1
1.23
1.258

(3 個資料列受到影響)

*/