anchor.diff:  DBCC:                            D B C C;
   DEALLOCATE:                      D E A L L O C A T E;
   DECLARE:                         D E C L A R E;
  -DEFAULT:                         D E F A U L T;
  +//DEFAULT:                         D E F A U L T;
   DELETE:                          D E L E T E;
   DENY:                            D E N Y;
   DESC:                            D E S C;
  
positive.code:       for_clause? option_clause? ';'?
      ;
  
  // https://msdn.microsoft.com/en-us/library/ms174335.aspx
  insert_statement
      : with_expression?
        INSERT (TOP '(' expression ')' PERCENT?)?
        INTO? (ddl_object | rowset_function_limited)
        with_table_hints?
        ('(' column_name_list ')')?
        output_clause?
        (VALUES '(' expression_list ')' (',' '(' expression_list ')')* |
                 derived_table | execute_statement | dml_table_source | DEFAULT VALUES)
        for_clause? option_clause? ';'?
      ;
  
  // https://msdn.microsoft.com/en-us/library/ms189499.aspx
  select_statement
      : with_expression? EXACT? query_expression order_by_clause? limit_clause? confidence_clause? ';'?
  
negative.code:     | fetch_cursor
      // https://msdn.microsoft.com/en-us/library/ms190500(v=sql.120).aspx
      | OPEN GLOBAL? cursor_name ';'?
      ;
  
  execute_var_string
  