Oracle9i New Feature Series: MERGE Statement - Insert or Update ("Upsert")

MERGE is a new SQL statement introduced in Oracle9i to update or insert rows selected from one table to another based on a condition. This avoids writing multiple DML statements to satisfy a conditional update or insert. The syntax is:

MERGE [hint] INTO [schema .] table [t_alias] USING [schema .] 

{ table | view | subquery } [t_alias] ON ( condition ) 

WHEN MATCHED THEN UPDATE SET column = { expr | DEFAULT } [, column = { expr | DEFAULT }]...

WHEN NOT MATCHED THEN INSERT ( column [, column]... ) VALUES ( expr [, expr]... )

Read more at:

OTN 9i Daily Feature – April 30

Oracle9i Documentation – SQL Reference – MERGE Statement