# MERGE INTO
<a name="querying-iceberg-merge-into"></a>

Conditionally updates, deletes, or inserts rows into an Iceberg table. A single statement can combine update, delete, and insert actions. For syntax, see [MERGE INTO](merge-into-statement.md).

**Note**  
`MERGE INTO` is transactional and is supported only for Apache Iceberg tables in Athena engine version 3.

The following example deletes all customers from table `t` that are in the source table `s`.

```
MERGE INTO accounts t USING monthly_accounts_update s
ON t.customer = s.customer
WHEN MATCHED
THEN DELETE
```

The following example updates target table `t` with customer information from source table `s`. For customer rows in table `t` that have matching customer rows in table `s`, the example increments the purchases in table t. If table `t` has no match for a customer row in table `s`, the example inserts the customer row from table `s` into table `t`.

```
MERGE INTO accounts t USING monthly_accounts_update s
    ON (t.customer = s.customer)
    WHEN MATCHED
        THEN UPDATE SET purchases = s.purchases + t.purchases
    WHEN NOT MATCHED
        THEN INSERT (customer, purchases, address)
              VALUES(s.customer, s.purchases, s.address)
```

The following example conditionally updates target table `t` with information from the source table `s`. The example deletes any matching target row for which the source address is Centreville. For all other matching rows, the example adds the source purchases and sets the target address to the source address. If there is no match in the target table, the example inserts the row from the source table.

```
MERGE INTO accounts t USING monthly_accounts_update s
    ON (t.customer = s.customer)
    WHEN MATCHED AND s.address = 'Centreville'
        THEN DELETE
    WHEN MATCHED
        THEN UPDATE
            SET purchases = s.purchases + t.purchases, address = s.address
    WHEN NOT MATCHED
        THEN INSERT (customer, purchases, address)
              VALUES(s.customer, s.purchases, s.address)
```