# SQL, how to update data

> Learn how to update data in a SQL table with the UPDATE command, and why the WHERE clause matters so you do not accidentally change every row.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2020-03-31 | Topics: [Database](https://flaviocopes.com/tags/database/) | Canonical: https://flaviocopes.com/sql-update-data/

The data stored in a table can be updated using the `UPDATE` command:

```sql
UPDATE people SET age=2 WHERE name='Roger'
```

It's important to add the `WHERE` clause, otherwise this instruction:

```sql
UPDATE people SET age=2
```

would update all rows in the table.