-20165 AN SQL DATA CHANGE STATEMENT WITHIN A FROM CLAUSE IS NOT ALLOWED IN THE CONTEXT IN WHICH IT WAS SPECIFIED

Explanation
  An SQL data change statement
cannot be specified in the FROM clause in specific contexts.
The
SQL data change statement must be the only table-reference in
the FROM clause that is used in: the outer fullselect of a SELECT statement (a subselect)
a SELECT INTO statement

System action
  The statement cannot be processed.

Programmer response
  Change the statement so
that the SQL data change statement within a FROM clause is used in
a supported context or is the only table-reference in
the FROM clause.

SQLSTATE
  428FL