---
title: "Explain the difference between a clustered index and a non-clustered index in SQL Server."  
description: "Explain the difference between a clustered index and a non-clustered index in SQL Server."  
author: "Utpal Vishwas"  
published: 2023-05-16  
updated: 2023-05-16  
canonical: https://www.mindstick.com/forum/158349/explain-the-difference-between-a-clustered-index-and-a-non-clustered-index-in-sql-server  
category: "mssql server"  
tags: ["sql server", "index", "sql"]  
reading_time: 2 minutes  

---

# Explain the difference between a clustered index and a non-clustered index in SQL Server.

[Explain the difference](https://www.mindstick.com/forum/156125/can-you-explain-the-difference-between-organic-and-paid-results) between a [clustered index](https://www.mindstick.com/blog/337/clustered-non-clustered-indexing-in-sql-server) and a non-clustered index in [SQL Server](https://www.mindstick.com/articles/12999/what-is-table-valued-function-in-sql-server).

## Replies

### Reply by Aryan Kumar

A [clustered](https://www.mindstick.com/interview/1892/what-is-a-clustered-index) [index](https://www.mindstick.com/blog/198/index-in-sql-server) is a special type of index in [SQL](https://www.mindstick.com/articles/13115/types-of-keys-in-sql-or-oracle-database) Server that physically orders the data in a table. A non-clustered index is an index that does not physically order the data in a table, but instead stores a pointer to the data in the clustered index.

In SQL Server, each table can have only one clustered index. The clustered index is used to physically order the data in the table, and all queries against the table are executed against the clustered index.

A non-clustered index can be created on any column or set of columns in a table. Non-clustered indexes are used to improve the performance of queries that are frequently executed against a specific column or set of columns.

The main [difference](https://www.mindstick.com/articles/157114/good-news-or-bad-news-and-the-difference-is) between a clustered index and a non-clustered index is that a clustered index physically orders the data in a table, while a non-clustered index does not.

Here is a table that summarizes the differences between clustered indexes and non-clustered indexes:

| Feature | Clustered Index | Non-Clustered Index |
| --- | --- | --- |
| Number per table | 1 | Unlimited |
| Physical order of data | Yes | No |
| Used for queries | Yes | Yes, for queries on the indexed columns |
| Storage | Leaf nodes contain the actual data | Leaf nodes contain a pointer to the data in the clustered index |


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Original Source: https://www.mindstick.com/forum/158349/explain-the-difference-between-a-clustered-index-and-a-non-clustered-index-in-sql-server

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