If the condition is not true for any rows, then the database inserts into the target table based on the corresponding source table row.
Specify the if you want Oracle Database to execute the insert operation only if the specified condition is true.The condition can refer only to the data source table.Oracle Database skips the insert operation for all rows for which the condition is not true.statement to select rows from one or more sources for update or insertion into a table or view.You can specify conditions to determine whether to update or insert into the target table or view.
This statement is a convenient way to combine multiple operations.
It lets you avoid multiple clause to specify the target table or view you are updating or inserting into.
In order to merge data into a view, the view must be updatable.
Refer to "Notes on Updatable Views" for more information.
USING Clause Use the operation either updates or inserts.
For each row in the target table for which the search condition is true, Oracle Database updates the row with corresponding data from the source table.