where 条件下列的多个值

Question

我有一张桌子如下

create table auto
(
  ID number,
  SEQ number,
  COLUMN_NME varchar2(10),
  RELATIONAL_OPERATOR varchar2(20),
  COLUMN_VALUE varchar2(20)
);

insert into auto SELECT 1,1,'HONDA','=','ACCORD' FROM DUAL;
insert into auto SELECT 1,2,'ENGINE','=','V6' FROM DUAL;
insert into auto SELECT 1,3,'COLOR','=','BLACK' FROM DUAL;
insert into auto SELECT 1,4,'COLOR','=','BLUE' FROM DUAL;
insert into auto SELECT 2,1,'TOYOTA','=','SIENNA' FROM DUAL;
insert into auto SELECT 2,2,'COLOR','=','BLACK' FROM DUAL;
insert into auto SELECT 2,3,'ENGINE','<>','V6' FROM DUAL;
insert into auto SELECT 3,1,'HONDA','=','ODYSSEY' FROM DUAL;
insert into auto SELECT 3,1,'COLOR','<>','BLACK' FROM DUAL;
insert into auto SELECT 3,1,'ENGINE','=','V6' FROM DUAL;
insert into auto SELECT 3,1,'HONDA','=','CRV' FROM DUAL;

我需要结果在哪里

• column_nme = '本田'，COLUMN_VALUE = '雅阁'
• COLUMN_NME=“颜色”，COLUMN_VALUE=“黑色”
• COLUMN_NME = '引擎'，COLUMN_VALUE = 'V6'

（考虑所有 RELATIONAL_OPERATOR 都是“=”）

我尝试使用案例陈述来编写

select ID,SEQ,case when column_nme = 'HONDA' and column_value = 'ACCORD' THEN 1 ELSE 0 END HONDA,
 CASE WHEN COLUMN_NME = 'ENGINE' AND COLUMN_VALUE = 'V6' THEN 1 ELSE 0 END ENGINE,
 CASE WHEN COLUMN_NME = 'COLOR' AND COLUMN_VALUE = 'BLACK' THEN 1 ELSE 0 END COLOR
 FROM AUTO;

我需要此表的 ID，其中 HONDA = 1，ENGINE = 1 AND COLOR = 1

Answer 1

您的表 auto 是一个 EAV（实体属性值）表，并且您希望 ID 匹配所有三个条件：

• 本田 = 雅阁
• 颜色 = 黑色
• 发动机=V6

查询 EAV 表的典型方法是通过聚合：获取具有所有所需匹配项的所有 ID：

select id
from auto
group by id
having count(case when column_nme = 'HONDA'  and relational_operator = '=' and column_value = 'ACCORD' then 1 end) > 0
   and count(case when column_nme = 'COLOR'  and relational_operator = '=' and column_value = 'BLACK'  then 1 end) > 0
   and count(case when column_nme = 'ENGINE' and relational_operator = '=' and column_value = 'V6'     then 1 end) > 0;

演示：https://dbfiddle.uk/NEDty7pP