我正在尝试将法语字符串(语言 ID 1)合并到一列中。到目前为止,我能够在 table1.title
和 table2.translated_topic
中获取法语字符串,但不确定如何连接它们。
版本:Postgres 9.6.0
源表架构:
表 1:knowledgebase_topics
id | title | language_id |
------------------------------------
64 | The Topic | 91 |
65 | The Topic 2 | 91 |
62 | Le fav sujet | 1 |
63 | Le fav sujet 2 | 1 |
61 | le bonjour | 1 |
表 2:knowledgebase_topics_translations
id | translated_topic| knowledgebase_topic_id | language_id |
-------------------------------------------------------------
| Le sujet | 64 | 1 |
| Le sujet 2 | 65 | 1 |
| Fav The Topic | 62 | 91 |
| Fav The Topic 2 | 63 | 91 |
给定以下查询:
SELECT title, translated_topic, "kbt".language_id, "kbtt".language_id
FROM knowledgebase_topics as "kbt"
LEFT JOIN knowledgebase_topics_translations as "kbtt" on ("kbtt".knowledgebase_topic_id = "kbt".id)
INNER JOIN knowledgebase_topics_organizations as "kbto" on ("kbto".knowledgebase_topic_id = "kbt".id)
WHERE "kbto"."organization_id" = 1
AND to_tsvector("kbt".title) @@ to_tsquery('le')
OR to_tsvector("kbtt".translated_topic) @@ to_tsquery('le')
AND "kbt".language_id = 1
OR "kbtt".language_id = 1;
我得到以下结果:
title | translated_topic | language_id | language_id
----------------+------------------+-------------+-------------
The Topic | Le sujet | 91 | 1
The Topic 2 | Le sujet 2 | 91 | 1
Le fav sujet | Fav The Topic | 1 | 91
Le fav sujet 2 | Fav The Topic 2 | 1 | 91
le bonjour | | 1 |
期望的结果:table1.title
和table2.translated_topics
已根据language_id == 1
合并.两个表都有一个语言 ID 列。
title | language_id
----------------+--------------
Le sujet | 1
Le sujet 2 | 1
Le fav sujet | 1
Le fav sujet 2 | 1
le bonjour | 1
我该怎么做?
注意:我不是单纯的想查lang IDs = 1,比如
and "kbt".language_id = 1 AND (instead of OR) "kbtt".language_id = 1;
因为这会导致语言 ID 1 的表 2
中缺少 2 条记录:
title | translated_topic | language_id | language_id
----------------+------------------+-------------+-------------
Le fav sujet | Fav The Topic | 1 | 91
Le fav sujet 2 | Fav The Topic 2 | 1 | 91
le bonjour | | 1 |
那么,我已经让它工作了......但这性能好吗?
SELECT title, "kbt".language_id
FROM knowledgebase_topics as "kbt"
INNER JOIN knowledgebase_topics_organizations as "kbto" on ("kbto".knowledgebase_topic_id = "kbt".id)
WHERE "kbto"."organization_id" = 1
AND to_tsvector("kbt".title) @@ to_tsquery('le')
AND "kbt".language_id = 1
UNION ALL
SELECT translated_topic, "kbtt".language_id
FROM knowledgebase_topics_translations as "kbtt"
INNER JOIN knowledgebase_topics_organizations as "kbto" on ("kbto".knowledgebase_topic_id = "kbtt".id)
WHERE "kbto"."organization_id" = 1
AND to_tsvector("kbtt".translated_topic) @@ to_tsquery('le')
AND "kbtt".language_id = 1;
给出输出:
title | language_id
----------------+-------------
le bonjour | 1
Le fav sujet | 1
Le fav sujet 2 | 1
Le sujet | 1
Le sujet 2 | 1
(5 rows)
最佳答案
设置回答问题的环境
首先,观察我们如何使用简洁的 DDL 最好地描述问题。最好在未来,你会学习如何写这样的问题..
CREATE TEMPORARY TABLE knowledgebase_topics AS
SELECT * FROM ( VALUES
(64,'The Topic',91),
(65,'The Topic 2',91),
(62,'Le fav sujet',1),
(63,'Le fav sujet 2',1),
(61,'le bonjour',1)
) AS t(knowledgebase_topic_id, title, language_id);
CREATE TEMPORARY TABLE knowledgebase_topics_translations AS
SELECT * FROM ( VALUES
('Le sujet' ,64,1 ),
('Le sujet 2' ,65,1 ),
('Fav The Topic' ,62,91 ),
('Fav The Topic 2',63,91 )
) AS t(translated_topic, knowledgebase_topic_id, language_id);
然后您只需告诉我们您想要什么,我们就可以轻松搭建工作环境并回答您的问题。不需要英语!对我们双方都更轻松。
解决方案
这里我们使用 UNION ALL
我们将其包装在 SELECT
中所以我们可以按 id 排序,并轻松地在一个地方更改 language
您正在寻找的。p>
SELECT title, language_id
FROM (
SELECT knowledgebase_topic_id, title, language_id
FROM knowledgebase_topics
UNION ALL
SELECT knowledgebase_topic_id, translated_topic, language_id
FROM knowledgebase_topics_translations
) AS t(id, title, language_id)
WHERE language_id = 1
ORDER BY id;
输出
title │ language_id
────────────────┼─────────────
le bonjour │ 1
Le fav sujet │ 1
Le fav sujet 2 │ 1
Le sujet │ 1
Le sujet 2 │ 1
(5 rows)
关于postgresql - 根据表值合并两列,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/41625097/