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Jak provádět počty v hierarchické tabulce Oracle založené na nadřazeném odkazu?

Chcete-li vybrat data, zkuste toto:

with xyz as (
    select tech_type,
        connect_by_root(link_id) as root_link_id,
        connect_by_root(group_id) as root_group_id
    from tech_values
    start with parent_group_id = 0
    connect by prior group_id = parent_group_id
)
select root_link_id, root_group_id,
    a_tech_type as tech_type_a, b_tech_type as tech_type_b, c_tech_type as tech_type_c
from xyz pivot (
        count(1) as tech_type
        for tech_type in (
            'A' as A,
            'B' as B,
            'C' as C
        ))
;

Na testovací sadě 39 000 záznamů trvalo Intel Core i5 s Oracle 11.2 (a vyprázdněnou vyrovnávací pamětí) přibližně 0,15 s, než to vypočítal. Doufám, že to bude dostatečně rychlé, aby uspokojilo vaše potřeby.

Chcete-li aktualizovat cílovou tabulku těmito daty, buď projděte výše uvedený SELECT a aktualizujte link_counts iterativně, nebo jednoduše použijte MERGE prohlášení:

merge into link_counts T
using (
    with xyz as (
        select tech_type,
            connect_by_root(link_id) as root_link_id,
            connect_by_root(group_id) as root_group_id
        from tech_values X
        start with parent_group_id = 0
        connect by prior group_id = parent_group_id
    )
    select *
    from xyz pivot (
            count(1) as tech_type
            for tech_type in (
                'A' as A,
                'B' as B,
                'C' as C
            ))
) S
on ( T.group_id = S.root_group_id )
when matched then
    update
    set T.tech_type_a = S.a_tech_type,
        T.tech_type_b = S.b_tech_type,
        T.tech_type_c = S.c_tech_type
when not matched then
    insert (link_id, group_id, tech_type_a, tech_type_b, tech_type_c)
    values (S.root_link_id, S.root_group_id, S.a_tech_type, S.b_tech_type, S.c_tech_type)
;

MERGE předpokládá, že GROUP_ID je primární/jedinečný klíč v link_counts stůl. Skutečná definice tech_values tabulka v původní otázce tento předpoklad podporuje.

Spool testovacího běhu v SQL*Plus je následující:

SQL> 
SQL> select count(1)
  2  from user_indexes
  3  where table_name = 'TECH_VALUES'
  4  ;

  COUNT(1)
----------
         0

SQL> 
SQL> select count(1)
  2  from user_constraints
  3  where table_name = 'TECH_VALUES'
  4      and constraint_type != 'C'
  5  ;

  COUNT(1)
----------
         0

SQL> 
SQL> alter system flush buffer_cache;

System altered.

SQL> alter system flush shared_pool;

System altered.

SQL> 
SQL> select systimestamp from dual;

SYSTIMESTAMP
---------------------------------------------------------------------------
08.06.14 23:18:40,053000 +02:00

SQL> 
SQL> select tech_type, count(1)
  2  from tech_values
  3  where parent_group_id != 0
  4  group by rollup(tech_type);

T   COUNT(1)
- ----------
A      20048
B      39984
C      19984
       80016

SQL> 
SQL> select systimestamp from dual;

SYSTIMESTAMP
---------------------------------------------------------------------------
08.06.14 23:18:40,144000 +02:00

SQL> 
SQL> alter system flush buffer_cache;

System altered.

SQL> alter system flush shared_pool;

System altered.

SQL> 
SQL> select systimestamp from dual;

SYSTIMESTAMP
---------------------------------------------------------------------------
08.06.14 23:18:40,246000 +02:00

SQL> 
SQL> with xyz as (
  2      select connect_by_root(link_id) as root_link_id, connect_by_root(group_id) as root_group_id, tech_type
  3      from tech_values X
  4      start with parent_group_id = 0
  5      connect by prior group_id = parent_group_id
  6  )
  7  select *
  8  from xyz pivot (
  9          count(1) as tech_type
 10          for tech_type in (
 11          'A' as A,
 12          'B' as B,
 13          'C' as C
 14          ));

ROOT_LINK_ID                                                     ROOT_GROUP_ID A_TECH_TYPE B_TECH_TYPE C_TECH_TYPE
---------------------------------------------------------------- ------------- ----------- ----------- -----------
LETTER_B                                                                  1800        3667        7482        3854
LETTER_B                                                                   200        3712        7583        3708
LETTER_C                                                                   300        6326       12450        6229
LETTER_A                                                                   100        6343       12469        6193

SQL> 
SQL> select *
  2  from table(dbms_xplan.display_cursor())
  3  ;

PLAN_TABLE_OUTPUT
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SQL_ID  59hmrtw6q3f4u, child number 0
-------------------------------------
with xyz as (     select connect_by_root(link_id) as root_link_id,
connect_by_root(group_id) as root_group_id, tech_type     from
tech_values X     start with parent_group_id = 0     connect by prior
group_id = parent_group_id ) select * from xyz pivot (         count(1)
as tech_type         for tech_type in (             'A' as A,
  'B' as B,             'C' as C         ))

Plan hash value: 3833790953

-------------------------------------------------------------------------------------------
| Id  | Operation                   | Name        | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT            |             |       |       |   563 (100)|          |
|   1 |  HASH GROUP BY PIVOT        |             | 29102 |  1420K|   563   (1)| 01:23:35 |
|   2 |   VIEW                      |             | 29102 |  1420K|  1044  (47)| 02:35:00 |
|*  3 |    CONNECT BY WITH FILTERING|             |       |       |            |          |
|*  4 |     TABLE ACCESS FULL       | TECH_VALUES |     4 |    84 |   187   (0)| 00:27:46 |
|*  5 |     HASH JOIN               |             | 29098 |   966K|   375   (1)| 00:55:41 |
|   6 |      CONNECT BY PUMP        |             |       |       |            |          |
|   7 |      TABLE ACCESS FULL      | TECH_VALUES | 80020 |  1641K|   187   (0)| 00:27:46 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   3 - access("PARENT_GROUP_ID"=PRIOR NULL)
   4 - filter("PARENT_GROUP_ID"=0)
   5 - access("connect$_by$_pump$_002"."prior group_id "="PARENT_GROUP_ID")


31 rows selected.

SQL> 
SQL> select systimestamp from dual;

SYSTIMESTAMP
---------------------------------------------------------------------------
08.06.14 23:18:40,805000 +02:00

SQL> 
SQL> spool off



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