多部分几何：提取部分时获取行和部分编号（通过 SDO_UTIL.EXTRACT_ALL）

Question

我在 Oracle 18c 中有多个部分 SDO_GEOMETRIES。

我可以使用 SDO_UTIL.EXTRACT_ALL() 函数将 部分 提取为单独的行：

with cte as (
--Each part is wrapped in brackets and separated by commas: (p1),(p2)
select sdo_geometry('MULTILINESTRING((1 1 1, 2 2 2),(3 3 3, 4 4 4))')    as shape from dual union all --3D: (X,Y,Z)
select sdo_geometry('MULTILINESTRING((5 5, 6 6),(7 7, 8 8),(9 9, 0 0))') as shape from dual union all --2D: (X,Y)
select sdo_geometry('MULTILINESTRING((1 1, 2 2))')                       as shape from dual           --2D: (X,Y)
    )
select
    a.object_value,
    sdo_util.to_wktgeometry(a.object_value)
from
    cte,
    table(sdo_util.extract_all(shape)) a

OBJECT_VALUE         SDO_UTIL.TO_WKTGEOMETRY(A.OBJECT_VALUE)                                         
-------------------- ---------------------------------------
[MDSYS.SDO_GEOMETRY] LINESTRING (1.0 1.0 1.0, 2.0 2.0 2.0)                                           
[MDSYS.SDO_GEOMETRY] LINESTRING (3.0 3.0 3.0, 4.0 4.0 4.0)                                           
[MDSYS.SDO_GEOMETRY] LINESTRING (5.0 5.0, 6.0 6.0)                                                   
[MDSYS.SDO_GEOMETRY] LINESTRING (7.0 7.0, 8.0 8.0)                                                   
[MDSYS.SDO_GEOMETRY] LINESTRING (9.0 9.0, 0.0 0.0)                                                   
[MDSYS.SDO_GEOMETRY] LINESTRING (1.0 1.0, 2.0 2.0)

db<>fiddle here

---

我想将以下列添加到查询中：

• MULTILINE_NUM（原多部分行号）
• PART_NUM

MULTILINE_NUM PART_NUM OBJECT_VALUE         SDO_UTIL.TO_WKTGEOMETRY(A.OBJECT_VALUE)                               

------------- -------- -------------------- ---------------------------------------
            1        1 [MDSYS.SDO_GEOMETRY] LINESTRING (1.0 1.0 1.0, 2.0 2.0 2.0)                                           
            1        2 [MDSYS.SDO_GEOMETRY] LINESTRING (3.0 3.0 3.0, 4.0 4.0 4.0)                                           
            2        1 [MDSYS.SDO_GEOMETRY] LINESTRING (5.0 5.0, 6.0 6.0)                                                   
            2        2 [MDSYS.SDO_GEOMETRY] LINESTRING (7.0 7.0, 8.0 8.0)                                                   
            2        3 [MDSYS.SDO_GEOMETRY] LINESTRING (9.0 9.0, 0.0 0.0)                                                   
            3        1 [MDSYS.SDO_GEOMETRY] LINESTRING (1.0 1.0, 2.0 2.0)

添加这些列时，我不想在事后使用 window 函数等“伪装”

我想直接从几何图形中提取该信息，以确保数字正确（即零件编号不应该是任意的；它应该反映原始几何图形的零件编号顺序）。

---

有没有办法从 table(sdo_util.extract_all(shape)) 查询中获取 MULTILINE_NUM 和 PART_NUM？

Answer 1

适配，你可以使用：

with cte (shape) as (
  --Each part is wrapped in brackets and separated by commas: (p1),(p2)
  select sdo_geometry('MULTILINESTRING((1 1 1, 2 2 2),(3 3 3, 4 4 4))')    from dual union all --3D: (X,Y,Z)
  select sdo_geometry('MULTILINESTRING((5 5, 6 6),(7 7, 8 8),(9 9, 0 0))') from dual union all --2D: (X,Y)
  select sdo_geometry('MULTILINESTRING((1 1, 2 2))')                       from dual           --2D: (X,Y)
)
select c.multiline_num,
       e.part_no,
       sdo_util.to_wktgeometry(e.elem)
from   ( SELECT ROWNUM AS multiline_num,
                shape
         FROM   cte
       ) c
       CROSS JOIN LATERAL (
         SELECT LEVEL AS part_no,
                SDO_UTIL.EXTRACT(c.shape, LEVEL) AS elem
         FROM   DUAL
         CONNECT BY LEVEL <= SDO_UTIL.GETNUMELEM(c.shape)
       ) e;

输出：

MULTILINE_NUM	PART_NO	SDO_UTIL.TO_WKTGEOMETRY(E.ELEM)
1	1	LINESTRING (1.0 1.0 1.0, 2.0 2.0 2.0)
1	2	LINESTRING (3.0 3.0 3.0, 4.0 4.0 4.0)
2	1	LINESTRING (5.0 5.0, 6.0 6.0)
2	2	LINESTRING (7.0 7.0, 8.0 8.0)
2	3	LINESTRING (9.0 9.0, 0.0 0.0)
3	1	LINESTRING (1.0 1.0, 2.0 2.0)

---

或者，使用 SDO_UTIL.EXTRACT_ALL:

with cte (shape) as (
  --Each part is wrapped in brackets and separated by commas: (p1),(p2)
  select sdo_geometry('MULTILINESTRING((1 1 1, 2 2 2),(3 3 3, 4 4 4))')    from dual union all --3D: (X,Y,Z)
  select sdo_geometry('MULTILINESTRING((5 5, 6 6),(7 7, 8 8),(9 9, 0 0))') from dual union all --2D: (X,Y)
  select sdo_geometry('MULTILINESTRING((1 1, 2 2))')                       from dual           --2D: (X,Y)
)
select c.multiline_num,
       e.part_no,
       sdo_util.to_wktgeometry(e.elem)
from   ( SELECT ROWNUM AS multiline_num,
                shape
         FROM   cte
       ) c
       CROSS JOIN LATERAL (
         SELECT ROWNUM AS part_no,
                a.object_value AS elem
         FROM   TABLE(SDO_UTIL.EXTRACT_ALL(c.shape)) a
       ) e;

输出相同。

db<>fiddle here