Question

对于下面的表结构，我无法构建所需的输出，不确定是否需要应用转置，我不具备丰富的知识。用于表创建和数据插入的SQL脚本将在最后给出。

输出应采用以下格式，如上所示，输出结果的ID_MAX_VAL应为主源表中每个制造商 - 国家/地区组合的最大ID。我需要获取每个制造商 - 国家/地区组合的最大ID，并显示/使用它们发送报告。

输出：

MANUFACTURER    COUNTRY     ID_MAX_VAL
--------------------------------------
NISSAN          USA         10
NISSAN          UK          30
HONDA           USA         80
HONDA           UK          70

注意：这是一个测试数据和表格结构，用于模拟实际的业务需求。

类似于我提到的表的视图是我们唯一可以访问的视图，它是我们唯一的来源。只能与之合作。

SQL脚本：

CREATE TABLE TB_TEST_01 
(
  ID NUMBER(6) NOT NULL 
, PARAM_NM VARCHAR2(200) NOT NULL 
, PARAM_VAL VARCHAR2(200) 
);
/

INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (10, 'MANUFACTURER', 'NISSAN');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (10, 'COUNTRY', 'USA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (30, 'MANUFACTURER', 'NISSAN');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (30, 'COUNTRY', 'UK');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (20, 'MANUFACTURER', 'NISSAN');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (20, 'COUNTRY', 'UK');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (50, 'MANUFACTURER', 'HONDA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (50, 'COUNTRY', 'USA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (60, 'MANUFACTURER', 'HONDA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (60, 'COUNTRY', 'USA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (80, 'MANUFACTURER', 'HONDA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (80, 'COUNTRY', 'USA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (70, 'MANUFACTURER', 'HONDA');
INSERT INTO TB_TEST_01 (ID, PARAM_NM, PARAM_VAL) VALUES (70, 'COUNTRY', 'UK')
;
/
COMMIT;

Answer 1

您也可以使用PIVOT功能：

select M_PARAM_VAL MANUFACTURER, C_PARAM_VAL COUNTRY, max(ID) ID_MAX_VAL
  from TB_TEST_01
 pivot (min(PARAM_VAL) as PARAM_VAL for (PARAM_NM) in ('MANUFACTURER' as M, 'COUNTRY' as C))
group by M_PARAM_VAL, C_PARAM_VAL;

输出：

| MANUFACTURER | COUNTRY | ID_MAX_VAL |
|--------------|---------|------------|
|        HONDA |      UK |         70 |
|       NISSAN |     USA |         10 |
|       NISSAN |      UK |         30 |
|        HONDA |     USA |         80 |

Answer 2

如果没有标准化设计，我们可以自行加入表格，如下图所示。

SELECT T1.PARAM_VAL AS MANUFACTURER,
       T2.PARAM_VAL AS COUNTRY,
       MAX(T1.ID) AS MAX_ID_VAL
FROM TB_TEST_01 T1,TB_TEST_01 T2
WHERE
       T1.ID = T2.ID
   AND T1.PARAM_NM='MANUFACTURER'
   AND T2.PARAM_NM='COUNTRY'
GROUP BY
   T1.PARAM_VAL,T2.PARAM_VAL

Answer 3

试试这个

CREATE TABLE TB_TEST_01 
(
  ID NUMBER(6) NOT NULL 
, MANUFACTURER VARCHAR2(200) NOT NULL 
, COUNTRY VARCHAR2(200) 
);
/

INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (10, 'NISSAN', 'USA');
INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (20, 'NISSAN', 'UK');
INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (30, 'NISSAN', 'UK');
INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (50, 'HONDA', 'USA');
INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (60, 'HONDA', 'USA');
INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (70, 'HONDA', 'UK');
INSERT INTO TB_TEST_01 (ID, MANUFACTURER, COUNTRY) VALUES (80, 'HONDA', 'USA');

COMMIT;
/

和出局

SELECT manufacturer, country,MAX(ID) id_max FROM TB_TEST_01
GROUP BY manufacturer,country;

Answer 4

@San @OracleUser 感谢所有人的帮助和不同类型的解决方案.. PIVOT，SELF JOIN .. :) （我是PIVOT的新手，还需要了解它是如何工作的）

我这样使用它来获取特定制造商的详细信息：

SELECT T1.PARAM_VAL AS MANUFACTURER,
       T2.PARAM_VAL AS COUNTRY,
       MAX(T1.ID) AS MAX_ID_VAL
FROM TB_TEST_01 T1,TB_TEST_01 T2
WHERE
       T1.ID = T2.ID
   AND T1.PARAM_NM='MANUFACTURER'
   AND T2.PARAM_NM='COUNTRY'
   AND T1.PARAM_VAL='HONDA'
GROUP BY
   T1.PARAM_VAL,T2.PARAM_VAL;

Oracle SQL查询 - 需要帮助

4 个答案: