各位兄弟,以下是我遇到的问题
传统order by后用rownum=1抓数据,和用分析函数Last_Value()抓数据,发现二者结果不一致。为嘛呢?..
Last_Value()抓的数据 21C* 是对的,order by之后感觉自动忽视了部分where条件,感觉抓到SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID里order by的第一个值。PS:传统order by的方式最内层的子查询,在部分版本的ORACLE可能识别不到T.PMDP。
我的版本可以..
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bi
PL/SQL Release 10.2.0.1.0 - Production
CORE 10.2.0.1.0 Production
TNS for 64-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL> select co,pmdp,mpid from t;CO PMDP MPID
------------ ------------------------ ------------------------------------
6 2111 C*SQL> SELECT co,orgnlvdp,mpid,pmcen FROM txd000paa41 WHERE co='6' AND mpid='C*';CO ORGNLVDP MPID
------------ ------------------------ ------------------------------------
PMCEN
------------------------
6 21 C*
21C*6 2113 C*
11C**
SQL> SELECT
2 (SELECT PMCEN FROM
3 (
4 SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
5 AND ORGNLVDP= CASE
6 WHEN ORGNLVDP=T.PMDP THEN T.PMDP
7 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
8 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
9 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
10 ELSE NULL END
11 ORDER BY Length(ORGNLVDP) DESC
12 ) WHERE ROWNUM=1
13 )PMCEN
14 FROM T;PMCEN
------------------------
11C**SQL> SELECT
2 (SELECT DISTINCT Last_Value(PMCEN) over (ORDER BY Length(ORGNLVDP) ROWS BETWEEN unbounded pr
eceding AND unbounded following)
3 FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID AND ORGNLVDP= CASE WHEN ORGNLVDP=T.PMDP THEN
T.PMDP
4 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
5 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
6 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
7 ELSE NULL END
8 )pmcen
9 FROM T;PMCEN
------------------------
21C*
--===============补充执行计划如下=================
SQL> explain plan FOR
2 SELECT
3 (SELECT PMCEN FROM
4 (
5 SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
6 AND ORGNLVDP= CASE
7 WHEN ORGNLVDP=T.PMDP THEN T.PMDP
8 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
9 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
10 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
11 ELSE NULL END
12 ORDER BY Length(ORGNLVDP) DESC
13 ) WHERE ROWNUM=1
14 )PMCEN
15 FROM T;已做解釋.SQL>
SQL> select * from table(DBMS_XPLAN.Display);PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 416088130--------------------------------------------------------------------------------
-------| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Tim
e |--------------------------------------------------------------------------------
-------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 10 | 3 (0)| 00:
00:01 ||* 1 | COUNT STOPKEY | | | | |
|| 2 | VIEW | | 15 | 120 | 4 (25)| 00:
00:01 ||* 3 | SORT ORDER BY STOPKEY| | 15 | 225 | 4 (25)| 00:
00:01 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------| 4 | TABLE ACCESS FULL | TXD000PAA41 | 15 | 225 | 3 (0)| 00:
00:01 || 5 | TABLE ACCESS FULL | T | 1 | 10 | 3 (0)| 00:
00:01 |--------------------------------------------------------------------------------
-------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
--------------------------------------------------- 1 - filter(ROWNUM=1)
3 - filter(ROWNUM=1)已選取 18 個資料列.SQL> explain plan FOR
2 SELECT
3 (SELECT DISTINCT Last_Value(PMCEN) over (ORDER BY Length(ORGNLVDP) ROWS BETWEEN unbounded pr
eceding AND unbounded following)
4 FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID AND ORGNLVDP= CASE WHEN ORGNLVDP=T.PMDP THEN
T.PMDP
5 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
6 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
7 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
8 ELSE NULL END
9 )pmcen
10 FROM T;已做解釋.SQL>
SQL>
SQL> select * from table(DBMS_XPLAN.Display);PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1796841893--------------------------------------------------------------------------------
----------------| Id | Operation | Name | Rows | Bytes | Cost (%
CPU)| Time |--------------------------------------------------------------------------------
----------------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 10 | 3
(0)| 00:00:01 || 1 | HASH UNIQUE | | 1 | 15 | 4
(50)| 00:00:01 || 2 | WINDOW SORT | | 1 | 15 | 4
(50)| 00:00:01 || 3 | TABLE ACCESS BY INDEX ROWID| TXD000PAA41 | 1 | 15 | 2
(0)| 00:00:01 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------|* 4 | INDEX RANGE SCAN | PK_TXD000PAA41 | 1 | | 1
(0)| 00:00:01 || 5 | TABLE ACCESS FULL | T | 1 | 10 | 3
(0)| 00:00:01 |--------------------------------------------------------------------------------
----------------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
--------------------------------------------------- 4 - access("CO"=:B1 AND "MPID"=:B2)
filter("MPID"=:B1 AND "ORGNLVDP"=CASE "ORGNLVDP" WHEN :B2 THEN :B3 WHEN
SUBSTR(:B4,1,3) THEN SUBSTR(:B5,1,3) WHEN SUBSTR(:B6,1,2) THEN SUB
STR(:B7,1,2) WHEN SUBSTR(:B8,1,1) THEN SUBSTR(:B9,1,1) ELSE NULL END )已選取 20 個資料列.
传统order by后用rownum=1抓数据,和用分析函数Last_Value()抓数据,发现二者结果不一致。为嘛呢?..
Last_Value()抓的数据 21C* 是对的,order by之后感觉自动忽视了部分where条件,感觉抓到SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID里order by的第一个值。PS:传统order by的方式最内层的子查询,在部分版本的ORACLE可能识别不到T.PMDP。
我的版本可以..
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bi
PL/SQL Release 10.2.0.1.0 - Production
CORE 10.2.0.1.0 Production
TNS for 64-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL> select co,pmdp,mpid from t;CO PMDP MPID
------------ ------------------------ ------------------------------------
6 2111 C*SQL> SELECT co,orgnlvdp,mpid,pmcen FROM txd000paa41 WHERE co='6' AND mpid='C*';CO ORGNLVDP MPID
------------ ------------------------ ------------------------------------
PMCEN
------------------------
6 21 C*
21C*6 2113 C*
11C**
SQL> SELECT
2 (SELECT PMCEN FROM
3 (
4 SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
5 AND ORGNLVDP= CASE
6 WHEN ORGNLVDP=T.PMDP THEN T.PMDP
7 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
8 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
9 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
10 ELSE NULL END
11 ORDER BY Length(ORGNLVDP) DESC
12 ) WHERE ROWNUM=1
13 )PMCEN
14 FROM T;PMCEN
------------------------
11C**SQL> SELECT
2 (SELECT DISTINCT Last_Value(PMCEN) over (ORDER BY Length(ORGNLVDP) ROWS BETWEEN unbounded pr
eceding AND unbounded following)
3 FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID AND ORGNLVDP= CASE WHEN ORGNLVDP=T.PMDP THEN
T.PMDP
4 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
5 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
6 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
7 ELSE NULL END
8 )pmcen
9 FROM T;PMCEN
------------------------
21C*
--===============补充执行计划如下=================
SQL> explain plan FOR
2 SELECT
3 (SELECT PMCEN FROM
4 (
5 SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
6 AND ORGNLVDP= CASE
7 WHEN ORGNLVDP=T.PMDP THEN T.PMDP
8 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
9 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
10 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
11 ELSE NULL END
12 ORDER BY Length(ORGNLVDP) DESC
13 ) WHERE ROWNUM=1
14 )PMCEN
15 FROM T;已做解釋.SQL>
SQL> select * from table(DBMS_XPLAN.Display);PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 416088130--------------------------------------------------------------------------------
-------| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Tim
e |--------------------------------------------------------------------------------
-------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 10 | 3 (0)| 00:
00:01 ||* 1 | COUNT STOPKEY | | | | |
|| 2 | VIEW | | 15 | 120 | 4 (25)| 00:
00:01 ||* 3 | SORT ORDER BY STOPKEY| | 15 | 225 | 4 (25)| 00:
00:01 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------| 4 | TABLE ACCESS FULL | TXD000PAA41 | 15 | 225 | 3 (0)| 00:
00:01 || 5 | TABLE ACCESS FULL | T | 1 | 10 | 3 (0)| 00:
00:01 |--------------------------------------------------------------------------------
-------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
--------------------------------------------------- 1 - filter(ROWNUM=1)
3 - filter(ROWNUM=1)已選取 18 個資料列.SQL> explain plan FOR
2 SELECT
3 (SELECT DISTINCT Last_Value(PMCEN) over (ORDER BY Length(ORGNLVDP) ROWS BETWEEN unbounded pr
eceding AND unbounded following)
4 FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID AND ORGNLVDP= CASE WHEN ORGNLVDP=T.PMDP THEN
T.PMDP
5 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
6 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
7 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
8 ELSE NULL END
9 )pmcen
10 FROM T;已做解釋.SQL>
SQL>
SQL> select * from table(DBMS_XPLAN.Display);PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Plan hash value: 1796841893--------------------------------------------------------------------------------
----------------| Id | Operation | Name | Rows | Bytes | Cost (%
CPU)| Time |--------------------------------------------------------------------------------
----------------
PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 10 | 3
(0)| 00:00:01 || 1 | HASH UNIQUE | | 1 | 15 | 4
(50)| 00:00:01 || 2 | WINDOW SORT | | 1 | 15 | 4
(50)| 00:00:01 || 3 | TABLE ACCESS BY INDEX ROWID| TXD000PAA41 | 1 | 15 | 2
(0)| 00:00:01 |PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------|* 4 | INDEX RANGE SCAN | PK_TXD000PAA41 | 1 | | 1
(0)| 00:00:01 || 5 | TABLE ACCESS FULL | T | 1 | 10 | 3
(0)| 00:00:01 |--------------------------------------------------------------------------------
----------------PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
Predicate Information (identified by operation id):
--------------------------------------------------- 4 - access("CO"=:B1 AND "MPID"=:B2)
filter("MPID"=:B1 AND "ORGNLVDP"=CASE "ORGNLVDP" WHEN :B2 THEN :B3 WHEN
SUBSTR(:B4,1,3) THEN SUBSTR(:B5,1,3) WHEN SUBSTR(:B6,1,2) THEN SUB
STR(:B7,1,2) WHEN SUBSTR(:B8,1,1) THEN SUBSTR(:B9,1,1) ELSE NULL END )已選取 20 個資料列.
(SELECT PMCEN FROM
(
SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
AND ORGNLVDP= CASE
WHEN ORGNLVDP=T.PMDP THEN T.PMDP
WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
ELSE NULL END
ORDER BY Length(ORGNLVDP) DESC
) WHERE ROWNUM=1)
------------------------这句改成-------------------
(SELECT PMCEN FROM
(
SELECT rownum rw, PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
AND ORGNLVDP= CASE
WHEN ORGNLVDP=T.PMDP THEN T.PMDP
WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
ELSE NULL END
ORDER BY Length(ORGNLVDP) DESC
) WHERE rw=1)
SELECT PMCEN FROM
(
SELECT PMCEN
FROM txd000paa41,T
WHERE txd000paa41.CO=T.CO
AND txd000paa41.MPID=T.MPID
AND ORGNLVDP= CASE
WHEN ORGNLVDP=T.PMDP THEN T.PMDP
WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
ELSE NULL END
ORDER BY Length(ORGNLVDP) DESC
) WHERE ROWNUM=1
结果:
21C*
2 (SELECT PMCEN FROM
3 (
4 SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
5 AND ORGNLVDP= CASE
6 WHEN ORGNLVDP=T.PMDP THEN T.PMDP
7 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
8 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
9 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
10 ELSE NULL END
11 ORDER BY Length(ORGNLVDP) DESC
12 ) WHERE ROWNUM=1
13 )PMCEN
14 FROM T;如果把where rownum=1改成 where 1=1会怎么样呢?返回几条记录?
2 (SELECT PMCEN FROM
3 (
4 SELECT PMCEN FROM txd000paa41 WHERE CO=T.CO AND MPID=T.MPID
5 AND ORGNLVDP= CASE
6 WHEN ORGNLVDP=T.PMDP THEN T.PMDP
7 WHEN ORGNLVDP=SubStr(T.PMDP,1,3) THEN SubStr(T.PMDP,1,3)
8 WHEN ORGNLVDP=SubStr(T.PMDP,1,2) THEN SubStr(T.PMDP,1,2)
9 WHEN ORGNLVDP=SubStr(T.PMDP,1,1) THEN SubStr(T.PMDP,1,1)
10 ELSE NULL END
11 ORDER BY Length(ORGNLVDP) DESC
12 ) WHERE ROWNUM=1
13 )PMCEN
14 FROM T;如果把where rownum=1改成 where 1=1会怎么样呢?返回几条记录?
只是刚开始客户那边oracle的版本恰好可以识别那种写法,看起来也没错,结果就是会把where条件过滤了..
(select t.*, row_number() over (partition by a order by b desc ) rn from t)
where rn = 1; 类似这样