# Updating Data

Update data using the `UPDATE` statement. For example:

```default
UPDATE my_keyspace.users SET age = 78
  WHERE user_id = 123e4567-e89b-12d3-a456-426655440000;
```

Let’s break down the components of this `UPDATE` statement:

**Keyspace and Table**

`my_keyspace.users`: This specifies the keyspace and table from which you
want to update data. In this example, you are updating data in a table named
`my_table` within the `my_keyspace` keyspace.

**Column Update**

`SET age = 78`: This part of the statement specifies the update operation.
You are setting the value of the age column to `78` for rows that match
the specified restriction.

**WHERE Clause**

`WHERE user_id = 123e4567-e89b-12d3-a456-426655440000`: This part of
the statement specifies the affected partition key, which is mandatory.

#### NOTE
Unlike in SQL, `UPDATE` does not check the prior existence of the row by default:
the row is created if none existed before, and updated otherwise.
This behavior can be changed by using ScyllaDB’s
[Lightweight Transaction](https://docs.scylladb.com/manual/stable/features/lwt.html)
`IF NOT EXISTS` or `IF EXISTS` clauses.

In summary, the `UPDATE` statement in ScyllaDB is used to modify existing
data in a table. Always include a `WHERE` clause with a suitable restriction
to target the specific rows you want to update, and specify the changes you
want to make using the SET clause. This helps you ensure the accuracy and
precision of your updates.

See the details about the [UPDATE statement](https://docs.scylladb.com/manual/stable/cql/dml/update.html)
in the ScyllaDB documentation.