Cross-joining with a table object propagates rows (without needing Table() function)

Question

Oracle Spatial has a function called SDO_UTIL.GETVERTICES:

This function returns an object of MDSYS.VERTEX_SET_TYPE, which consists of a table of objects of MDSYS.VERTEX_TYPE.

CREATE TYPE vertex_set_type as TABLE OF vertex_type;

The GetVertices() function is typically used in conjunction with the Table() function. The geometry table is cross-joined with table(getvertices(shape)) to propagate vertex rows for each geometry:

with cte as (
select sdo_geometry('linestring (10 20, 30 40)')                       shape from dual union all
select sdo_geometry('linestring (50 60, 70 80, 90 100)')               shape from dual union all
select sdo_geometry('linestring (110 120, 130 140, 150 160, 170 180)') shape from dual)
  
select 
    v.*
from 
    cte, table(sdo_util.getvertices(shape)) v

    X     Y     Z     W    V5    V6    V7    V8    V9   V10   V11    ID
----- ----- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
   10    20                                                           1
   30    40                                                           2
   50    60                                                           1
   70    80                                                           2
   90   100                                                           3
  110   120                                                           1
  130   140                                                           2
  150   160                                                           3
  170   180                                                           4

And the examples in the docs suggest using Table() as well.

But from a quick test, using the table() function doesn't seem to be necessary. If I remove the Table() function from the query, it produces the same result.

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Question:

How is it possible that cross-joining with a table object propagates rows — without needing the Table() function?

The docs suggest that we should use the Table() function, so I wonder if that was correct in older versions of Oracle, but maybe something changed in newer versions?

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Related:

• At what version did the TABLE() keyword for table collection expressions become optional?
• Cross join to varray without using Table() expression

Answer 1

How is it possible that cross-joining with a table object propagates rows — without needing the Table() function?

In either Oracle 12 or Oracle 18, the TABLE keyword for table collection expressions was made an optional part of the syntax so:

SELECT *
FROM   TABLE(SYS.ODCIVARCHAR2LIST('a', 'b', 'c'));

Will work on all oracle versions (that support collections).

And:

SELECT *
FROM   SYS.ODCIVARCHAR2LIST('a', 'b', 'c');

Will work from Oracle 18 (and maybe Oracle 12) and do exactly the same thing (but would raise syntax errors in earlier versions).

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I'm trying to find the documentation for the new feature but so far haven't found it.