blocks|key|5249006|text|聚集索引|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5249007|5249008|每个表只有一个|unordered-list-item|5249009|读取速度比非集群快，因为数据实际存储在索引顺序|5249010|中|5249011|非聚集索引|5249012|对于每个表，可以多次使用|5249013|5249014|进行插入和更新操作，比使用聚集索引|5249015|更快|5249016|当选择包含使用索引的字段的数据时，这两种类型的索引都会提高性能，但会降低更新和插入操作的速度。|5249017|由于insert和update速度较慢，聚集索引应该设置在通常是递增的ie或时间戳的字段上。|5249018|SQL+Server通常仅在选择性高于95%25时才使用索引。|5249019|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|11|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|12|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|13|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|14|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|15|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|16|8|@]|9|@]|A|$]]|$1|N|3|-4|5|E|7|17|8|@]|9|@]|A|$]]|$1|O|3|P|5|E|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|19|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1A|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1B|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]]|Z|$]]

Clustered Index

<ul>
<li>Only one per table</li>
<li>Faster to read than non clustered as data is physically stored in index order</li>
</ul>

Non Clustered Index

<ul>
<li>Can be used many times per table</li>
<li>Quicker for insert and update operations than a clustered index</li>
</ul>

Both types of index will improve performance when select data with fields that use the index but will slow down update and insert operations.

Because of the slower insert and update clustered indexes should be set on a field that is normally incremental ie Id or Timestamp.

SQL Server will normally only use an index if its selectivity is above 95%.

blocks|key|2994268|text|聚集索引对磁盘上的数据进行物理排序。这意味着索引不需要额外的数据，但只能有一个聚集索引(显然)。使用聚集索引访问数据是最快的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2994269|所有其他索引必须是非聚集的。非聚集索引具有索引列中数据的副本，这些数据与指向实际数据行的指针(如果有聚集索引，则指向聚集索引)保持有序。这意味着通过非聚集索引访问数据必须经过额外的间接层。但是，如果只选择索引列中可用的数据，则可以直接从复制的索引数据中获取数据(这就是为什么最好只选择需要的列，而不使用*)|2994270|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Clustered indexes physically order the data on the disk. This means no extra data is needed for the index, but there can be only one clustered index (obviously). Accessing data using a clustered index is fastest.

All other indexes must be non-clustered. A non-clustered index has a duplicate of the data from the indexed columns kept ordered together with pointers to the actual data rows (pointers to the clustered index if there is one). This means that accessing data through a non-clustered index has to go through an extra layer of indirection. However if you select only the data that's available in the indexed columns you can get the data back directly from the duplicated index data (that's why it's a good idea to SELECT only the columns that you need and not use *)

blocks|key|5248895|text|聚集索引以物理方式存储在表中。这意味着它们是最快的，并且每个表只能有一个聚集索引。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5248896|非聚集索引是单独存储的，您可以拥有任意多的索引。|5248897|最好的选择是在最常用的唯一列(通常是PK+)上设置聚集索引。您的表中应该始终有一个选择良好的聚集索引，除非出现一个非常令人信服的原因--想不到一个聚集索引，但是嘿，它可能就在那里--因为没有这样做。|5248898|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

Clustered indexes are stored physically on the table. This means they are the fastest and you can only have one clustered index per table. 

Non-clustered indexes are stored separately, and you can have as many as you want.

The best option is to set your clustered index on the most used unique column, usually the PK. You should always have a well selected clustered index in your tables, unless a very compelling reason--can't think of a single one, but hey, it may be out there--for not doing so comes up.

blocks|key|3838875|text|聚集索引|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3838876|3838877|一个表只能有一个聚集索引。|ordered-list-item|3838878|通常在主键上创建。|3838879|聚集索引的叶节点包含数据页。|3838880|3838881|非聚集索引|3838882|SQL键最多只能有249个非聚集索引(在|3838883|+2005以后的版本中，最多可支持在any+key上创建999个非聚集索引。|3838884|，非聚集索引的叶节点不包含数据页。相反，叶节点包含索引行。|3838885|3838886|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|W|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|X|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|Z|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|11|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|12|8|@]|9|@]|A|$]]|$1|O|3|P|5|E|7|13|8|@]|9|@]|A|$]]|$1|Q|3|R|5|E|7|14|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|15|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|U|$]]

<h2>Clustered Index</h2>

<ol>
<li>There can be only one clustered index for a table.</li>
<li>Usually made on the primary key.</li>
<li>The leaf nodes of a clustered index contain the data pages.</li>
</ol>

<h2>Non-Clustered Index</h2>

<ol>
<li>There can be only 249 non-clustered indexes for a table(till sql version 2005 later versions support upto 999 non-clustered indexes).</li>
<li>Usually made on the any key.</li>
<li>The leaf node of a nonclustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.</li>
</ol>

blocks|key|2994495|text|聚集索引|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2994496|2994497|表中只能有一个聚集索引|unordered-list-item|2994498|按顺序对记录进行排序并以物理方式存储记录|2994499|数据检索比非聚集索引更快|2994500|不需要额外空间来存储逻辑结构|2994501|2994502|非聚集索引|2994503|2994504|表中可以有任意数量的非聚集索引|2994505|不会影响物理顺序。为数据行创建逻辑顺序并使用指向物理数据文件的指针|2994506|数据插入/更新比聚集索引更快|2994507|使用额外空间存储逻辑结构|2994508|2994509|2994510|除了这些区别之外，您还必须知道，当表是非聚集的(当表没有聚集索引时)，数据文件是无序的，并且它使用Heap数据结构作为数据结构。|2994511|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|14|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|15|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|16|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|17|8|@]|9|@]|A|$]]|$1|J|3|K|5|E|7|18|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1A|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|P|3|Q|5|E|7|1C|8|@]|9|@]|A|$]]|$1|R|3|S|5|E|7|1D|8|@]|9|@]|A|$]]|$1|T|3|U|5|E|7|1E|8|@]|9|@]|A|$]]|$1|V|3|W|5|E|7|1F|8|@]|9|@]|A|$]]|$1|X|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|1I|8|@]|9|@]|A|$]]|$1|11|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|12|$]]

<h2>Clustered Index</h2>

<ul>
<li>Only one clustered index can be there in a table</li>
<li>Sort the records and store them physically according to the order</li>
<li>Data retrieval is faster than non-clustered indexes</li>
<li>Do not need extra space to store logical structure</li>
</ul>

<h2>Non Clustered Index</h2>

<ul>
<li>There can be any number of non-clustered indexes in a table</li>
<li>Do not affect the physical order. Create a logical order for data rows and use pointers to physical data files</li>
<li>Data insertion/update is faster than clustered index</li>
<li>Use extra space to store logical structure</li>
</ul>

<hr>

Apart from these differences you have to know that when table is non-clustered (when the table doesn't have a clustered index) data files are unordered and it uses Heap data structure as the data structure.

blocks|key|2994202|text|优势：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2994203|聚集索引非常适合范围(例如，select+*+from+my_table+where+my_key介于@min和@max之间)|2994204|在某些情况下，如果使用orderby语句，DBMS将不必执行排序工作。|2994205|缺点：|2994206|聚集索引可能会减慢插入速度，因为如果新的键不是按顺序排列的，则在放入记录时必须修改记录的物理布局。|2994207|entityMap^0|0|3|0|0|0|0|3|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|S|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|T|8|@]|D|@]|E|$]]|$1|J|3|K|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|X|8|@]|D|@]|E|$]]|$1|N|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|O|$]]

Pros:

Clustered indexes work great for ranges (e.g. select * from my_table where my_key between @min and @max)

In some conditions, the DBMS will not have to do work to sort if you use an orderby statement.

Cons:

Clustered indexes are can slow down inserts because the physical layouts of the records have to be modified as records are put in if the new keys are not in sequential order.

blocks|key|3838618|text|聚类基本上意味着数据在表中的物理顺序。这就是为什么每个表只能有一个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3838619|Unclustered意味着它“只”是一个逻辑顺序。|3838620|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Clustered basically means that the data is in that physical order in the table. This is why you can have only one per table.

Unclustered means it's "only" a logical order.

blocks|key|5248947|text|聚集索引实际上描述了记录在磁盘上物理存储的顺序，因此只能有一个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5248948|非聚集索引定义的逻辑顺序与磁盘上的物理顺序不匹配。|5248949|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

A clustered index actually describes the order in which records are physically stored on the disk, hence the reason you can only have one.

A Non-Clustered Index defines a logical order that does not match the physical order on disk.

blocks|key|5249330|text|索引数据库有两个部分:一组按任意顺序排列的物理记录，以及一组标识读取记录以产生按某种标准排序的结果的顺序的索引。如果物理排列和索引之间没有相关性，那么按顺序读出所有记录可能需要进行大量独立的单个记录读取操作。由于数据库可能能够在比读取两个非连续记录所花费的时间更少的时间内读取数十个连续记录，因此如果索引中连续的记录也被连续地存储在磁盘上，则性能可以被提高。指定索引是集群的将导致数据库做出一些努力(不同的数据库在多大程度上不同)来安排事情，以便索引中连续的记录组在磁盘上将是连续的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5249331|例如，如果要从一个空的非集群数据库开始，并按随机顺序添加10,000条记录，则这些记录很可能会按添加顺序添加到最后。按索引顺序读出数据库将需要10,000次单记录读取。但是，如果要使用集群数据库，系统可能会在添加每条记录时检查前一条记录是否是自己存储的；如果发现是这样，它可能会将该记录与数据库末尾的新记录一起写入。然后，它可以查看移动的记录曾经驻留的插槽之前的物理记录，并查看后面的记录是否自己存储。如果它发现是这种情况，它可以将该记录移动到该点。使用这种方法将导致许多记录成对地分组在一起，从而可能使顺序读取速度几乎翻一番。|5249332|实际上，集群数据库使用比这更复杂的算法。不过，需要注意的一件关键事情是，在更新数据库所需的时间和按顺序读取数据库所需的时间之间存在权衡。维护群集数据库将显著增加添加、删除或更新记录所需的工作量，这会影响排序顺序。如果按顺序读取数据库的频率比更新数据库的频率高得多，那么集群将是一个很大的优势。如果经常更新，但很少按顺序读出，则聚类可能会大大消耗性能，特别是在将项添加到数据库的顺序与它们相对于聚集索引的排序顺序无关的情况下。|5249333|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

An indexed database has two parts: a set of physical records, which are arranged in some arbitrary order, and a set of indexes which identify the sequence in which records should be read to yield a result sorted by some criterion. If there is no correlation between the physical arrangement and the index, then reading out all the records in order may require making lots of independent single-record read operations. Because a database may be able to read dozens of consecutive records in less time than it would take to read two non-consecutive records, performance may be improved if records which are consecutive in the index are also stored consecutively on disk. Specifying that an index is clustered will cause the database to make some effort (different databases differ as to how much) to arrange things so that groups of records which are consecutive in the index will be consecutive on disk.

For example, if one were to start with an empty non-clustered database and add 10,000 records in random sequence, the records would likely be added at the end in the order they were added. Reading out the database in order by the index would require 10,000 one-record reads. If one were to use a clustered database, however, the system might check when adding each record whether the previous record was stored by itself; if it found that to be the case, it might write that record with the new one at the end of the database. It could then look at the physical record before the slots where the moved records used to reside and see if the record that followed that was stored by itself. If it found that to be the case, it could move that record to that spot. Using this sort of approach would cause many records to be grouped together in pairs, thus potentially nearly doubling sequential read speed.

In reality, clustered databases use more sophisticated algorithms than this. A key thing to note, though, is that there is a tradeoff between the time required to update the database and the time required to read it sequentially. Maintaining a clustered database will significantly increase the amount of work required to add, remove, or update records in any way that would affect the sorting sequence. If the database will be read sequentially much more often than it will be updated, clustering can be a big win. If it will be updated often but seldom read out in sequence, clustering can be a big performance drain, especially if the sequence in which items are added to the database is independent of their sort order with regard to the clustered index.

blocks|key|2994175|text|聚集索引本质上是索引列中数据的排序副本。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2994176|聚集索引的主要优点是，当您的查询(查找)在索引中定位数据时，不需要额外的IO来检索该数据。|2994177|维护聚集索引的开销，尤其是在频繁更新的表中，可能会导致较差的性能，因此创建非聚集索引可能更可取。|2994178|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

A clustered index is essentially a sorted copy of the data in the indexed columns.

The main advantage of a clustered index is that when your query (seek) locates the data in the index then no additional IO is needed to retrieve that data.

The overhead of maintaining a clustered index, especially in a frequently updated table, can lead to poor performance and for that reason it may be preferable to create a non-clustered index.

blocks|key|3839276|text|你可能已经经历了上述帖子中的理论部分：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3839277|-The集群索引，因为我们可以直接看到要记录的点，也就是说，它是直接的，所以搜索所需的时间更少。此外，它不会占用任何额外的内存/空间来存储索引|offset|length|style|BOLD|3839278|-While，在非聚集索引中，它间接指向聚集索引，然后它将访问实际记录，由于其间接性质，它将花费更多的时间来access.Also它需要自己的内存/空间来存储索引|3839279|​|3839280|📷|atomic|3839281|3839282|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/9ab70c6ea03b70359a8b0244e353f0a3.png|imageAlt^0|0|0|1Z|0|0|29|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@$D|10|E|11|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|12|8|@$D|13|E|14|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|15|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|16|8|@]|9|@$D|17|E|18|1|19]]|A|$]]|$1|O|3|K|5|6|7|1A|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Q|$R|$5|S|T|U|A|$V|W|X|-4]]]]

You might have gone through theory part from the above posts:

-The clustered Index as we can see points directly to record i.e. its direct so it takes less time for a search. Additionally it will not take any extra memory/space to store the index

-While, in non-clustered Index, it indirectly points to the clustered Index then it will access the actual record, due to its indirect nature it will take some what more time to access.Also it needs its own memory/space to store the index

<a href="https://i.stack.imgur.com/kFSWR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kFSWR.png" alt="enter image description here"></a>

blocks|key|2994692|text|//从MSDN复制来的，非聚集索引的第二点在其他答案中没有明确提到。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2994693|群集|offset|length|style|BOLD|2994694|2994695|聚集索引根据数据行的键值对表或视图中的数据行进行排序和存储。这些是包含在索引定义中的列。每个表只能有一个聚集索引，因为数据行本身只能以一种顺序存储。|unordered-list-item|2994696|表中数据行按排序顺序存储的唯一时间是当表包含聚集索引时。当表具有聚集索引时，该表称为聚集表。如果表没有聚集索引，则其数据行存储在称为堆的无序结构中。|2994697|2994698|非群集|2994699|2994700|Nonclustered索引具有独立于数据行的结构。非聚集索引包含非聚集索引键值和|2994701|2994702|每个键值条目都有一个指向包含键值的数据行的指针。|2994703|从非聚集索引中的索引行指向数据行的指针称为行定位符。行定位器的结构取决于数据页是存储在堆中还是存储在聚集表中。对于堆，行定位器是指向该行的指针。对于聚集表，行定位符是聚集索引键。|2994704|2994705|entityMap^0|0|0|2|0|0|0|0|0|0|3|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|12|8|@$D|13|E|14|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|15|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|16|8|@]|9|@]|A|$]]|$1|L|3|M|5|K|7|17|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|18|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|19|8|@$D|1A|E|1B|F|G]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|R|3|S|5|K|7|1D|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1F|8|@]|9|@]|A|$]]|$1|W|3|X|5|K|7|1G|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1H|8|@]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1I|8|@]|9|@]|A|$]]]|10|$]]

// Copied from MSDN, the second point of non-clustered index is not clearly mentioned in the other answers. 

Clustered

<ul>
<li>Clustered indexes sort and store the data rows in the table or view
based on their key values. These are the columns included in the
index definition. There can be only one clustered index per table,
because the data rows themselves can be stored in only one order.</li>
<li>The only time the data rows in a table are stored in sorted order is
when the table contains a clustered index. When a table has a
clustered index, the table is called a clustered table. If a table
has no clustered index, its data rows are stored in an unordered
structure called a heap.</li>
</ul>

Nonclustered

<ul>
<li>Nonclustered indexes have a structure separate from the data rows. A 
nonclustered index contains the nonclustered index key values and 
each key value entry has a pointer to the data row that contains the 
key value.</li>
<li>The pointer from an index row in a nonclustered index to a data row
is called a row locator. The structure of the row locator depends on
whether the data pages are stored in a heap or a clustered table.
For a heap, a row locator is a pointer to the row. For a clustered
table, the row locator is the clustered index key.</li>
</ul>

blocks|key|5249843|text|聚集索引|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|5249844|5249845|聚集索引的检索速度更快，插入和更新速度更慢。|unordered-list-item|5249846|表只能有一个聚集索引。|5249847|不需要额外的空间来存储logical+structure.|5249848|Determines磁盘上数据的存储顺序。|5249849|5249850|非聚集索引|5249851|在检索数据时速度较慢，在插入和更新时速度较快。|5249852|5249853|表可以有多个非聚集索引。|5249854|5249855|5249856|需要额外空间来存储逻辑结构。|5249857|5249858|5249859|对在磁盘上存储数据的顺序没有影响。|5249860|5249861|entityMap^0|0|4|0|0|0|0|0|0|0|0|5|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|18|8|@$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]|$1|G|3|H|5|I|7|1C|8|@]|D|@]|E|$]]|$1|J|3|K|5|I|7|1D|8|@]|D|@]|E|$]]|$1|L|3|M|5|I|7|1E|8|@]|D|@]|E|$]]|$1|N|3|O|5|I|7|1F|8|@]|D|@]|E|$]]|$1|P|3|-4|5|6|7|1G|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1H|8|@$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|S|3|T|5|6|7|1K|8|@]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1L|8|@]|D|@]|E|$]]|$1|V|3|W|5|I|7|1M|8|@]|D|@]|E|$]]|$1|X|3|-4|5|6|7|1N|8|@]|D|@]|E|$]]|$1|Y|3|-4|5|6|7|1O|8|@]|D|@]|E|$]]|$1|Z|3|10|5|I|7|1P|8|@]|D|@]|E|$]]|$1|11|3|-4|5|6|7|1Q|8|@]|D|@]|E|$]]|$1|12|3|-4|5|6|7|1R|8|@]|D|@]|E|$]]|$1|13|3|14|5|I|7|1S|8|@]|D|@]|E|$]]|$1|15|3|-4|5|6|7|1T|8|@]|D|@]|E|$]]|$1|16|3|-4|5|6|7|1U|8|@]|D|@]|E|$]]]|17|$]]

Clustered Indexes
<ul>
<li>Clustered Indexes are faster for retrieval and slower for insertion
and update.</li>
<li>A table can have only one clustered index.</li>
<li>Don't require extra space to store logical structure.</li>
<li>Determines the order of storing the data on the disk.</li>
</ul>
Non-Clustered Indexes
<ul>
<li>Non-clustered indexes are slower in retrieving data and faster in
insertion and update.
</li>
<li>A table can have multiple non-clustered indexes.
</li>
<li>Require extra space to store logical structure.
</li>
<li>Has no effect of order of storing data on the disk.
</li>
</ul>

What are the differences between a <code>clustered</code> and a <code>non-clustered index</code>?

What are the differences between a clustered and a non-clustered index?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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