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Oracle：加入2个结果集

[英]Oracle : Join 2 result sets

 原文  2018-10-30 11:09:57  7   1    database/ oracle/ join/ resultset

问题描述

我被困住了，我需要一个建议如何将2个结果集合并为1个

第一个结果集具有针对不同安装点的阈值。 每个安装点都有一个带有非默认阈值的行，例如“ u01”-“ u08”。 所有其他安装点的默认阈值位于带有空MOUNTPOINT值的行中。 

HOSTNAME                       MOUNTPOINT             WARNING_PC CRITICAL_P
------------------------------ ---------------------- ---------- ----------
oracledatabase.domain.local                           20         5        <-- here is default
oracledatabase.domain.local    /opt/nfsshare/u01      20         19
oracledatabase.domain.local    /opt/nfsshare/u02      1.01       1
oracledatabase.domain.local    /opt/nfsshare/u03      1.01       1
oracledatabase.domain.local    /opt/nfsshare/u04      1.01       1
oracledatabase.domain.local    /opt/nfsshare/u05      1.01       1
oracledatabase.domain.local    /opt/nfsshare/u07      1.01       1
oracledatabase.domain.local    /opt/nfsshare/u08      1.01       1

第二个结果集包含所有安装点的列表 

HOSTNAME                       MOUNTPOINT
------------------------------ ----------------------------------------
oracledatabase.domain.local    /
oracledatabase.domain.local    /boot
oracledatabase.domain.local    /dev
oracledatabase.domain.local    /opt/nfsshare/u01
oracledatabase.domain.local    /opt/nfsshare/u02
oracledatabase.domain.local    /opt/nfsshare/u03
oracledatabase.domain.local    /opt/nfsshare/u04
oracledatabase.domain.local    /opt/nfsshare/u05
oracledatabase.domain.local    /opt/nfsshare/u06
oracledatabase.domain.local    /opt/nfsshare/u07
oracledatabase.domain.local    /opt/nfsshare/u08
oracledatabase.domain.local    /opt/nfsshare/u09
oracledatabase.domain.local    /opt/nfsshare/u10
oracledatabase.domain.local    /opt/nfsshare/u11
oracledatabase.domain.local    /opt/nfsshare/u12
oracledatabase.domain.local    /opt/nfsshare/u13

因此，我需要按以下方式加入它们：如果安装点在第一个结果集中具有阈值，则使用该值。 如果安装点没有阈值，则使用默认值 

HOSTNAME                       MOUNTPOINT           WARNING_PC CRITICAL_P
------------------------------ -------------------  ---------- ----------
oracledatabase.domain.local    /                    20         5
oracledatabase.domain.local    /boot                20         5
oracledatabase.domain.local    /dev                 20         5
oracledatabase.domain.local    /opt/nfsshare/u01    20         19
oracledatabase.domain.local    /opt/nfsshare/u02    1.01       1
oracledatabase.domain.local    /opt/nfsshare/u03    1.01       1
oracledatabase.domain.local    /opt/nfsshare/u04    1.01       1
oracledatabase.domain.local    /opt/nfsshare/u05    1.01       1
oracledatabase.domain.local    /opt/nfsshare/u06    20         5
oracledatabase.domain.local    /opt/nfsshare/u07    1.01       1
oracledatabase.domain.local    /opt/nfsshare/u08    1.01       1
oracledatabase.domain.local    /opt/nfsshare/u09    20         5
oracledatabase.domain.local    /opt/nfsshare/u10    20         5
oracledatabase.domain.local    /opt/nfsshare/u11    20         5
oracledatabase.domain.local    /opt/nfsshare/u12    20         5
oracledatabase.domain.local    /opt/nfsshare/u13    20         5

几个小时后添加。 看来我已经找到了解决方案。 但是可能有更好的方法 

COL HOSTNAME2 FOR A30
COL MOUNTPOINT2 FOR A30 

WITH THRESHOLDS AS (
SELECT TARGET_NAME "HOSTNAME1",
       DECODE(LENGTH(REPLACE(KEY_VALUE,CHR(32))),NULL,'DEFAULT',KEY_VALUE) "MOUNTPOINT1",
       WARNING_THRESHOLD "WARNING_PCT",
       CRITICAL_THRESHOLD "CRITICAL_PCT"
FROM
       SYSMAN.MGMT$METRIC_COLLECTION
WHERE
       TARGET_TYPE = 'host' AND
       METRIC_NAME = 'Filesystems' AND
       METRIC_COLUMN = 'pctAvailable' AND TARGET_NAME='oracledatabase.domain.local'
),
MOUNTPOINTS AS (
SELECT ENTITY_NAME "HOSTNAME2",
       KEY_PART_1  "MOUNTPOINT2"
FROM 
       SYSMAN.GC$METRIC_VALUES_LATEST
WHERE
       METRIC_GROUP_LABEL = 'Filesystems' AND  METRIC_COLUMN_NAME = 'available'
       AND ENTITY_NAME='oracledatabase.domain.local'
)
-- Get list of matching mountpoints
SELECT HOSTNAME2, MOUNTPOINT2, WARNING_PCT, CRITICAL_PCT FROM (
SELECT * FROM MOUNTPOINTS INNER JOIN  THRESHOLDS ON 
MOUNTPOINTS.MOUNTPOINT2=THRESHOLDS.MOUNTPOINT1)
-- Union
UNION ALL
-- Get list mountpoints with default threshold
SELECT HOSTNAME2, MOUNTPOINT2, WARNING_PCT, CRITICAL_PCT FROM
(SELECT * FROM MOUNTPOINTS WHERE MOUNTPOINT2 NOT IN (SELECT MOUNTPOINT1 FROM THRESHOLDS)),
(SELECT * FROM THRESHOLDS WHERE MOUNTPOINT1='DEFAULT') 
ORDER BY 2;

HOSTNAME2                      MOUNTPOINT2                    WARNING_PC CRITICAL_PCT
------------------------------ ------------------------------ ---------- --------------------
oracledatabase.domain.local    /                              20         5
oracledatabase.domain.local    /boot                          20         5
oracledatabase.domain.local    /dev                           20         5
oracledatabase.domain.local    /opt/nfsshare/u01              20         19
oracledatabase.domain.local    /opt/nfsshare/u02              1.01       1
oracledatabase.domain.local    /opt/nfsshare/u03              1.01       1
oracledatabase.domain.local    /opt/nfsshare/u04              1.01       1
oracledatabase.domain.local    /opt/nfsshare/u05              1.01       1
oracledatabase.domain.local    /opt/nfsshare/u06              20         5
oracledatabase.domain.local    /opt/nfsshare/u07              1.01       1
oracledatabase.domain.local    /opt/nfsshare/u08              1.01       1
oracledatabase.domain.local    /opt/nfsshare/u09              20         5
oracledatabase.domain.local    /opt/nfsshare/u10              20         5
oracledatabase.domain.local    /opt/nfsshare/u11              20         5
oracledatabase.domain.local    /opt/nfsshare/u12              20         5
oracledatabase.domain.local    /opt/nfsshare/u13              20         5

16 rows selected.


有关“ rs”的详细信息。 评论（仅供我参考）


如果没有COALESCE功能，则更容易理解其工作原理。 

WITH THRESHOLDS AS (
SELECT TARGET_NAME "HOSTNAME1",
       KEY_VALUE "MOUNTPOINT1",
       WARNING_THRESHOLD "WARNING_PCT",
       CRITICAL_THRESHOLD "CRITICAL_PCT"
FROM
       SYSMAN.MGMT$METRIC_COLLECTION
WHERE
       TARGET_TYPE = 'host' AND
       METRIC_NAME = 'Filesystems' AND
       METRIC_COLUMN = 'pctAvailable' AND TARGET_NAME='oracledatabase.domain.local'
),
MOUNTPOINTS AS (
SELECT ENTITY_NAME "HOSTNAME2",
       KEY_PART_1  "MOUNTPOINT2"
FROM 
       SYSMAN.GC$METRIC_VALUES_LATEST
WHERE
       METRIC_GROUP_LABEL = 'Filesystems' AND  METRIC_COLUMN_NAME = 'available'
       AND ENTITY_NAME='oracledatabase.domain.local'
)
SELECT A.HOSTNAME2, A.MOUNTPOINT2, 
       T1.WARNING_PCT "WRN_THR",
       T2.WARNING_PCT "WRN_DFL", 
       T1.CRITICAL_PCT "CRT_THR", 
       T2.CRITICAL_PCT "CRT_DFL"
FROM MOUNTPOINTS A
LEFT OUTER JOIN THRESHOLDS T1 ON A.MOUNTPOINT2 = T1.MOUNTPOINT1 --match
JOIN THRESHOLDS T2 ON COALESCE(TRIM(T2.MOUNTPOINT1),'DEFAULT') = 'DEFAULT';

HOSTNAME2                      MOUNTPOINT2          WRN_THR WRN_DFL CRT_THR CRT_DFL
------------------------------ -------------------- ------- ------- ------- -------
oracledatabase.domain.local    /opt/nfsshare/u01    20      20      19      5
oracledatabase.domain.local    /opt/nfsshare/u02    1.01    20      1       5
oracledatabase.domain.local    /opt/nfsshare/u03    1.01    20      1       5
oracledatabase.domain.local    /opt/nfsshare/u04    1.01    20      1       5
oracledatabase.domain.local    /opt/nfsshare/u05    1.01    20      1       5
oracledatabase.domain.local    /opt/nfsshare/u07    1.01    20      1       5
oracledatabase.domain.local    /opt/nfsshare/u08    1.01    20      1       5
oracledatabase.domain.local    /boot                        20              5
oracledatabase.domain.local    /opt/nfsshare/u06            20              5
oracledatabase.domain.local    /opt/nfsshare/u13            20              5
oracledatabase.domain.local    /dev                         20              5
oracledatabase.domain.local    /opt/nfsshare/u11            20              5
oracledatabase.domain.local    /opt/nfsshare/u12            20              5
oracledatabase.domain.local    /                            20              5
oracledatabase.domain.local    /opt/nfsshare/u10            20              5
oracledatabase.domain.local    /opt/nfsshare/u09            20              5

16 rows selected.

https://docs.oracle.com/cd/B28359_01/server.111/b28286/functions023.htm#SQLRF00617 COALESCE 返回表达式列表中的第一个非空expr 。 您必须至少指定两个表达式。 如果所有出现的expr评估为null，则该函数返回null。

1 个解决方案

解决方案1
 0  2018-10-30 14:42:39

您可以使用原始表，联接和无CTE来实现

例如，假设您的表是MOUNTPOINTS和THRESHOLDS： 

SELECT A.HOSTNAME, A.MOUNTPOINT, 
COALESCE(T1.WARNING_PCT,T2.WARNING_PCT) WARNING_PCT, 
COALESCE(T1.CRITICAL_PCT, T2.CRITICAL_PCT) CRITICAL_PCT
FROM MOUNTPOINTS A
LEFT OUTER JOIN THRESHOLDS T1 ON A.MOUNTPOINT = T1.MOUNTPOINT --match
JOIN THRESHOLDS T2 ON COALESCE(TRIM(T2.MOUNTPOINT),'DEFAULT') = 'DEFAULT'

请注意，如果它具有space（''）为空字符串（在oracle中被视为NULL），则在此处使用TRIM更改默认值。

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