declare @t table(a varchar(10))
insert into @t select 'ab'
union all select 'vd'
union all select 'gh'select * from @t order by left(a,1)
insert into @t select 'ab'
union all select 'vd'
union all select 'gh'select * from @t order by left(a,1)
"order by a " does not means that "order by left(a,1)"is better than "order by left(a,1)"
the reason is that