and a unique index is present and a duplicate row is concurrently

inserted, then a uniqueness violation error is raised;

<command>MERGE</command> does not attempt to avoid such

errors by evaluating <literal>MATCHED</literal> conditions.

errors by restarting evaluation of <literal>MATCHED</literal>

conditions.

</para>

<para>

filled with a default value, either its declared default value

or null if there is none.

</para>

<para>

If the expression for any column is not of the correct data type,

automatic type conversion will be attempted.

</para>

<para>

If <replaceable class="parameter">target_table_name</replaceable>

is a partitioned table, each row is routed to the appropriate partition

<programlisting>

MERGE INTO CustomerAccount CA

USING (Select CustomerId, TransactionValue From RecentTransactions) AS T

ON CA.CustomerId = T.CustomerId

ON T.CustomerId = CA.CustomerId

WHEN MATCHED THEN

UPDATE SET Balance = Balance + TransactionValue;

WHEN NOT MATCHED THEN

INSERT (CustomerId, Balance)

VALUES (T.CustomerId, T.TransactionValue)

WHEN MATCHED THEN

UPDATE SET Balance = Balance + TransactionValue;

</programlisting>

</para>