ASA SQL User's Guide
  Joins: Retrieving Data from Several Tables
    Joins overview

Using joins in delete, update, and insert statements

You can use joins in DELETE, UPDATE and INSERT statements, as well as in SELECT statements. You can update some cursors that contain joins if the ANSI_UPDATE_CONSTRAINTS option is set to OFF. This is the default for databases created before Adaptive Server Anywhere version 7. For databases created in version 7 or later, the default is ON.

For more information, see ANSI_UPDATE_CONSTRAINTS option [compatibility].