我在Oracle中具有以下实体-属性-值（EAV）表：
| ID | Key | Value | |----|-------------|--------------| | 1 | phone_num_1 | 111-111-1111 | | 1 | phone_num_2 | 222-222-2222 | | 1 | contact_1 | friend | | 1 | contact_2 | family | | 1 | first_name | mike | | 1 | last_name | smith | | 2 | phone_num_1 | 333-333-3333 | | 2 | phone_num_2 | 444-444-4444 | | 2 | contact_1 | family | | 2 | contact_2 | friend | | 2 | first_name | john | | 2 | last_name | adams | | 3 | phone_num_1 | 555-555-5555 | | 3 | phone_num_2 | 666-666-6666 | | 3 | phone_num_3 | 777-777-7777 | | 3 | contact_1 | work | | 3 | contact_2 | family | | 3 | contact_3 | friend | | 3 | first_name | mona | | 3 | last_name | lisa |
请注意，某些键已索引，因此与其他索引键有关联。例如，phone_num_1将与contact_1关联。
注意：索引数量没有硬性限制。可以有10、20甚至50个phone_num_ *，但是可以保证每个phone_num_N都有一个对应的contact_N
这是我想要的结果：
| ID | Phone_Num | Contact | First_Name | Last_Name | |----|--------------|---------|------------|-----------| | 1 | 111-111-1111 | friend | mike | smith | | 1 | 222-222-2222 | family | mike | smith | | 2 | 333-333-3333 | family | john | adams | | 2 | 444-444-4444 | friend | john | adams | | 3 | 555-555-5555 | work | mona | lisa | | 3 | 666-666-6666 | family | mona | lisa | | 3 | 777-777-7777 | friend | mona | lisa |
我尝试过/看过什么：
我研究了Oracle的枢纽功能；但是，我不相信这可以解决我的问题，因为我没有固定数量的属性要使用。 我看了这些帖子： SQL Query to return multiple key value pairs from a single table in one row
Pivot rows to columns without aggregate
问题：
我想用SQL完全完成的任务是什么？如果是这样，怎么办？如果没有，请解释原因。
非常感谢您的帮助，以下是附表，可帮助您入门：
with
table_1 ( id, key, value ) as (
select 1,'phone_num_1','111-111-1111' from dual union all
select 1,'phone_num_2','222-222-2222' from dual union all
select 1,'contact_1','friend' from dual union all
select 1,'contact_2','family' from dual union all
select 1,'first_name','mike' from dual union all
select 1,'last_name','smith' from dual union all
select 2,'phone_num_1','333-333-3333' from dual union all
select 2,'phone_num_2','444-444-4444' from dual union all
select 2,'contact_1','family' from dual union all
select 2,'contact_2','friend' from dual union all
select 2,'first_name','john' from dual union all
select 2,'last_name','adams' from dual union all
select 3,'phone_num_1','555-555-5555' from dual union all
select 3,'phone_num_2','666-666-6666' from dual union all
select 3,'phone_num_3','777-777-7777' from dual union all
select 3,'contact_1','work' from dual union all
select 3,'contact_2','family' from dual union all
select 3,'contact_3','friend' from dual union all
select 3,'first_name','mona' from dual union all
select 3,'last_name','lisa' from dual
)
select * from table_1;
答案 0 :(得分：1)
这很丑，但是我认为您需要做
select t1.* , t2.value, t3.n, t3.f
from table_1 t1
inner join table_1 t2 on t1.id = t2.id and REPLACE(t1.key, 'phone_num_', '') = REPLACE(t2.key, 'contact_', '')
inner join (
select ID, min(case when Key = 'first_name' then Value end) as n, min(case when Key = 'last_name' then Value end) as f
from table_1
group by ID
) t3 on t1.id = t3.id
where
t1.Key not in('first_name','last_name')
答案 1 :(得分：1)
这不是动态枢轴，因为您有一组固定的键-您只需要首先将键的枚举与键本身分开即可。
您需要：
phone_num和contact键前缀；然后Oracle设置：
CREATE TABLE table_1 ( id, key, value ) as
select 1,'phone_num_1','111-111-1111' from dual union all
select 1,'phone_num_2','222-222-2222' from dual union all
select 1,'contact_1','friend' from dual union all
select 1,'contact_2','family' from dual union all
select 1,'first_name','mike' from dual union all
select 1,'last_name','smith' from dual union all
select 2,'phone_num_1','333-333-3333' from dual union all
select 2,'phone_num_2','444-444-4444' from dual union all
select 2,'contact_1','family' from dual union all
select 2,'contact_2','friend' from dual union all
select 2,'first_name','john' from dual union all
select 2,'last_name','adams' from dual union all
select 3,'phone_num_1','555-555-5555' from dual union all
select 3,'phone_num_2','666-666-6666' from dual union all
select 3,'phone_num_3','777-777-7777' from dual union all
select 3,'contact_1','work' from dual union all
select 3,'contact_2','family' from dual union all
select 3,'contact_3','friend' from dual union all
select 3,'first_name','mona' from dual union all
select 3,'last_name','lisa' from dual
查询：
SELECT *
FROM (
SELECT id,
CASE
WHEN key LIKE 'phone_num_%' THEN 'phone_num'
WHEN key LIKE 'contact_%' THEN 'contact'
ELSE key
END AS key,
CASE
WHEN key LIKE 'phone_num_%'
OR key LIKE 'contact_%'
THEN TO_NUMBER( SUBSTR( key, INSTR( key, '_', -1 ) + 1 ) )
ELSE NULL
END AS item,
value,
MAX( CASE key WHEN 'first_name' THEN value END )
OVER ( PARTITION BY id ) AS first_name,
MAX( CASE key WHEN 'last_name' THEN value END )
OVER ( PARTITION BY id ) AS last_name
FROM table_1
)
PIVOT( MAX( value ) FOR key IN ( 'contact' AS contact, 'phone_num' AS phone_num ) )
WHERE item IS NOT NULL
ORDER BY id, item
输出：
ID | ITEM | FIRST_NAME | LAST_NAME | CONTACT | PHONE_NUM -: | ---: | :--------- | :-------- | :------ | :----------- 1 | 1 | mike | smith | friend | 111-111-1111 1 | 2 | mike | smith | family | 222-222-2222 2 | 1 | john | adams | family | 333-333-3333 2 | 2 | john | adams | friend | 444-444-4444 3 | 1 | mona | lisa | work | 555-555-5555 3 | 2 | mona | lisa | family | 666-666-6666 3 | 3 | mona | lisa | friend | 777-777-7777
db <>提琴here
如果您可以重构表，那么一个简单的改进就是添加一个额外的列来保存键的枚举，并在每个枚举通用的值时使用NULL：
CREATE TABLE table_1 ( id, key, line, value ) as
select 1, 'phone_num', 1, '111-111-1111' from dual union all
select 1, 'phone_num', 2, '222-222-2222' from dual union all
select 1, 'contact', 1, 'friend' from dual union all
select 1, 'contact', 2, 'family' from dual union all
select 1, 'first_name', NULL, 'mike' from dual union all
select 1, 'last_name', NULL, 'smith' from dual
那么您的密钥集始终是固定的，您无需从密钥中提取枚举值。
答案 2 :(得分：0)
选择ID，
电话，
联系，
first_value（last）IGNORE NULLS超过（按ID DESC按ID DESC划分的范围，在CURRENT行之间，并且在其后无边界）last_name，
first_value（FIRST）IGNORE NULLS over（按ID DESC范围按ID顺序划分，在CURRENT行与后无界之后）first_name
从
（选择ID，
值，
row_number（）over（partition by id，SUBSTR（KEY，1，instr（KEY，''，1）-1）by KEY order）rn，
SUBSTR（KEY，1，instr（KEY，''，1）-1）键
FROM table_1
）枢纽（MAX（value）FOR KEY IN（'phone'AS phone，'last'AS last，'first'AS FIRST，'contact'AS contact））
按ID排序；