You can use the SET DIALECT statement:

    o  In interactive SQL

    o  Embedded in host language programs to be precompiled to effect
       the processing of dynamic SQL statements (use the DIALECT
       clause to effect dialect changes in the precompiled source)

    o  As part of a procedure in an SQL module (but may not be in a
       compound statement)

    o  In dynamic SQL as a statement to be dynamically executed

    However, the ORACLE dialects can be used only in the interactive
    SQL and dynamic SQL environments.