针对组中顶级结果的SQL优化

我需要帮助优化查询的一部分，这部分查询的执行计划非常糟糕。表TB_供应商大约有500000行

SELECT K.supl_id
FROM TB_SUPPLIER T
WHERE T.SUPL_ID =
(
    SELECT DISTINCT
           FIRST_VALUE(SUP_ID) OVER(ORDER BY SUP_AVOB DESC NULLS LAST)
    FROM VW_SUPPLIER
    WHERE CORP_ID = T.SUPL_ID
          AND SUP_ACTIVE = 1
);    

不幸的是，内部零件VW_供应商的内容由视图提供，并且也有大约500000行。 你能给我推荐一种更有效的方法来获得完全相同的结果吗？

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提前感谢

感谢您的回答，我准备了一个测试用例：

CREATE TABLE TB_CS
   (    SUPL_ID number (8,0) not null,          
        CS_TYPE varchar2(10 char),
        CS_DEL  number (1,0),        
        constraint c_pk primary key (SUPL_ID) using index 
   )  ;

Insert into TB_CS (SUPL_ID,CS_TYPE,CS_DEL) values (35263391, 'C' , 0);
Insert into TB_CS (SUPL_ID,CS_TYPE,CS_DEL) values (35298444, 'C' , 0);
Insert into TB_CS (SUPL_ID,CS_TYPE,CS_DEL) values (35414837, 'C' , 0);  


CREATE TABLE TB_SUPPLIER
   (    SUPL_ID number (8,0) not null, 
        constraint s_pk primary key(SUPL_ID) using index 
    );


Insert into TB_SUPPLIER (SUPL_ID) values (35263391);
Insert into TB_SUPPLIER (SUPL_ID) values (35298444);
Insert into TB_SUPPLIER (SUPL_ID) values (35414837);    

create index IX_CS on  TB_CS (  CS_DEL, CS_TYPE, SUPL_ID )   ;

ALTER TABLE TB_SUPPLIER  ADD CONSTRAINT TB_CS_FK FOREIGN KEY ( supl_id )  REFERENCES TB_CS ( supl_id );   



CREATE TABLE VW_SUPPLIER
   (    SUP_ID   NUMBER(8,0) primary key, 
        CORP_ID      NUMBER(8,0), 
        SUP_AVOB    NUMBER, 
        SUP_ACTIVE NUMBER(1,0) 
   ) ;

Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35355998','35298444','6715','1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35358149','35298444','6390','1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35532593','35298444','68','1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35249072','35414837','66','1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35300318','35414837','32','1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35298289','35298444',null,'1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35578515','35263391',null,'1');
Insert into VW_SUPPLIER (SUP_ID,CORP_ID,SUP_AVOB,SUP_ACTIVE) values ('35274495','35263391',null,'1');

下面是问题查询：

    SELECT T.supl_id, V.*
FROM TB_SUPPLIER T
 JOIN TB_CS C ON T.SUPL_ID = C.SUPL_ID
 LEFT JOIN VW_SUPPLIER V ON V.CORP_ID = T.SUPL_ID 
WHERE C.CS_DEL = 0  AND C.CS_TYPE IN ('C','S')  and
      V.SUP_ID = (
            SELECT DISTINCT  -- could not removed because of the single-row subquery returns more than one row
                   FIRST_VALUE(SUP_ID) OVER(ORDER BY SUP_AVOB DESC NULLS LAST)
            FROM VW_SUPPLIER
            WHERE CORP_ID = T.SUPL_ID
                  AND SUP_ACTIVE = 1
        );  

。。这是预期的结果：

     "SUP_ID",  "CORP_ID","SUP_AVOB","SUP_ACTIVE"
  35355998, 35298444,  6715,      1
  35249072, 35414837,  66,        1
  35274495, 35263391, null,       1

实际系统的执行计划如下所示

-------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                                          | Name                           | Rows  | Bytes | Cost (%CPU)| Time     |
-------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                                   |                                |     1 |    39 |    25M (11)| 00:16:41 |
|   1 |  WINDOW BUFFER                                     |                                |     1 |    39 |    25M (11)| 00:16:41 |
|*  2 |   FILTER                                           |                                |       |       |            |          |
|   3 |    NESTED LOOPS                                    |                                |   221K|  8427K|    12M  (9)| 00:08:23 |
|   4 |     NESTED LOOPS                                   |                                |   221K|  7130K|    75   (4)| 00:00:01 |
|   5 |      INLIST ITERATOR                               |

                            |       |       |            |          |

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我不明白下面的选择。您是否将表TB\U SUPPLIER t加入到t.supl\u id=v.corp\u id上的视图VW\u SUPPLIER v中，但也加入到t.supl\u id=某个不同的第一个值上？您能否先对视图进行排序，可能会减少所选列的数量，然后将其连接到TB_供应商？此外，您能否向我们展示一些示例数据，尤其是VW_供应商的示例数据？当您说“…最终的执行计划非常糟糕”如果您能提供这样的执行计划，那将非常有帮助。

DISTINCT

子句肯定是无用的。除此之外，

WHERE T.SUPL\u ID=（选择SUP\u ID…WHERE CORP\u ID=T.SUPL\u ID…）

锁定有点奇怪。

K.SUPL\u ID

不存在。