以前也碰到ORA-28132: Merge into syntax does not support security policies 这个错误，原因是相关的表上定义了一些VPD的policy (可以查user_policies), 解决方法要么去掉这些policy，要么将Merge改成普通的insert/update语句。
但是今天发现同样的语句在11.2.0.2是不报错，但是在11.2.0.1上报错。查了下，原来在11.2.0.2这个问题被Oracle解决了！
http://docs.oracle.com/cd/E11882_01/server.112/e10592/statements_9016.htm
Note:
In previous releases of Oracle Database, when you created an Oracle Virtual Private Database policy on an application that included the MERGE INTO statement, the MERGEINTO statement would be prevented with an ORA-28132: Merge into syntax does not support security policies error, due to the presence of the Virtual Private Database policy. Beginning with Oracle Database 11g Release 2 (11.2.0.2), you can create policies on applications that include MERGE INTO operations. To do so, in theDBMS_RLS.ADD_POLICY statement_types parameter, include the INSERT, UPDATE, and DELETE statements, or just omit the statement_types parameter altogether. Refer to Oracle Database Security Guide for more information on enforcing policies on specific SQL statement types.
