SQL Server 2022

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create table [heap] 
  (
  id int,
  first_name nvarchar(10),
  family_name nvarchar(20)
  )
;
insert into [heap] (id, first_name, family_name) 
values
(4,'John', 'Nautilus'),
(2,'Erik', 'Dreadnaught'),
(1, 'J.D.', 'Edwards')
;
3 rows affected

select * from [heap];


id
first_name
family_name


4
John
Nautilus

2
Erik
Dreadnaught

1
J.D.
Edwards


create clustered index [cix_heap_family_name_PERF_20230321] on [heap] (family_name);
select * from [heap]; -- no longer a heap actually, but a clustered table


id
first_name
family_name


2
Erik
Dreadnaught

1
J.D.
Edwards

4
John
Nautilus


drop index [cix_heap_family_name_PERF_20230321] on [heap];
select * from heap; -- now a sorted heap


id
first_name
family_name


2
Erik
Dreadnaught

1
J.D.
Edwards

4
John
Nautilus


alter table [heap] rebuild;
select * from [heap];


id
first_name
family_name


2
Erik
Dreadnaught

1
J.D.
Edwards

4
John
Nautilus