> For the complete documentation index, see [llms.txt](https://gyansetu-sql.gitbook.io/sql-programming/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gyansetu-sql.gitbook.io/sql-programming/sql-database/sql-create-index-statement.md).

# CREATE INDEX

### SQL CREATE INDEX Statement

The CREATE INDEX statement is used to create indexes in tables.

Indexes are used to retrieve data from the database very fast. The users cannot see the indexes, they are just used to speed up searches/queries.

> **Note:** Updating a table with indexes takes more time than updating a table without (because the indexes also need an update). So, only create indexes on columns that will be frequently searched against.<br>

CREATE INDEX Syntax

Creates an index on a table. Duplicate values are allowed:

```sql
CREATE INDEX index_name
ON table_name (column1, column2, ...);
```

**CREATE UNIQUE INDEX Syntax**

Creates a unique index on a table. Duplicate values are not allowed:

```sql
CREATE UNIQUE INDEX index_name
ON table_name (column1, column2, ...);
```

**CREATE INDEX Example**

The SQL statement below creates an index named "idx\_lastname" on the "LastName" column in the "Persons" table:

```sql
CREATE INDEX idx_lastname
ON Persons (LastName);
```

If you want to create an index on a combination of columns, you can list the column names within the parentheses, separated by commas:

```sql
CREATE INDEX idx_pname
ON Persons (LastName, FirstName);
```

\
DROP INDEX Statement

The DROP INDEX statement is used to delete an index in a table.

**SQL Server:**

```sql
DROP INDEX table_name.index_name;
```

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INDEX
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