How to add index in SQL Server

By FoxLearn 7/2/2024 3:54:21 AM   39
In SQL Server, adding an index to a table can significantly improve the performance of queries, especially for columns frequently used in search conditions (WHERE clause), join conditions, or sorting operations.

Here’s how to add index in SQL Server.

Syntax

CREATE INDEX index_name
ON table_name (column1, column2, ...)

For example:

Let's say you have a table named Employees and you frequently search by the FirstName column.

CREATE INDEX idx_FirstName
ON Employees (FirstName)

Explanation:

  1. CREATE INDEX: This statement is used to create a new index on a table.

  2. index_name: This name must be unique within the database.

  3. ON table_name: The name of the table on which you want to create the index.

  4. (column1, column2, ...): You can create an index on a single column or multiple columns. The order of columns in the index definition can impact the index's effectiveness, especially if you have queries that filter or sort by multiple columns. 

If you need to remove an index, you can use the DROP INDEX statement.

DROP INDEX index_name ON table_name

Adding indexes can be a powerful tool to optimize query performance in SQL Server