mysql --如何将连接表连接到另一个具有父表值的连接表？

Question

我不知道如何在标题中正确地写出一个问题，但我会尽力解释我想要达到的目标。

这些是我的父表：

 hgs_meaning         hgs_word_types        hgs_transliterations
 +----+---------+    +----+-----------+    +----+-----------------+
 | id | meaning |    | id | word_type |    | id | transliteration |
 +----+---------+    +----+-----------+    +----+-----------------+
 | 3  | man     |    | 4  | noun      |    | 5  | mnjw            |
 +----+---------+    +----+-----------+    +----+-----------------+

这些是我的连接表：

 junc_meaning_word_type
 +----+------------+--------------+
 | id | meaning_id | word_type_id |
 +----+------------+--------------+
 | 2  | 3          | 4            |
 +----+------------+--------------+

 junc_transliteration_meaning_word_type
 +----+--------------------+----------------------+
 | id | transliteration_id | meaning_word_type_id |
 +----+--------------------+----------------------+
 | 1  | 5                  | 2                    |
 +----+--------------------+----------------------+

我知道如何使SELECT JOIN查询以获得junc_meaning_word_type表的结果，但不知道junc_transliteration_meaning_word_type的结果

我知道如何得到这个结果：

 +----+-----------------+-------------------+
 | id | transliteration | meaning_word_type |
 +----+-----------------+-------------------+
 | 1  | mnjw            | 2                 |
 +----+-----------------+-------------------+

我正在努力实现这个结果：

 +----+--------------------+------------+--------------+
 | id | transliteration_id | meaning_id | word_type_id |
 +----+--------------------+------------+--------------+
 | 1  | mnjw               | man        | noun         |
 +----+--------------------+------------+--------------+

这是怎么做到的。我猜想我需要使用嵌套的SELECT查询(子查询)或多个JOIN查询，但我不知道如何构造这样的查询。

以下是我的问题：

/* hgs_meanings and hgs_word_types join to junc_meaning_word_type */

SELECT junc_meaning_word_type.id, hgs_word_types.word_type, hgs_meanings.meaning
FROM junc_meaning_word_type
JOIN hgs_word_types ON junc_meaning_word_type.word_type_id = hgs_word_types.id
JOIN hgs_meanings ON junc_meaning_word_type.meaning_id = hgs_meanings.id 

/* hgs_transliterations and junc_meaning_word_type join to junc_transliteration_meaning */

SELECT junc_transliteration_meaning.id, hgs_transliterations.transliteration, junc_meaning_word_type.id
FROM junc_transliteration_meaning
JOIN hgs_transliterations ON junc_transliteration_meaning.transliteration_id = hgs_transliterations.id
JOIN junc_meaning_word_type ON junc_transliteration_meaning.meaning_word_type_id = junc_meaning_word_type.id

任何帮助都将不胜感激。

Answer 1

您可以简单地将所有表与其适当的连接关系一起JOIN，然后SELECT所需的特定列/表达式。您还可以使用SELECT子句中指定的列/表达式来显示它们的不同名称。

同样，为了代码清晰(可读性)和避免模棱两可的行为，在多表查询的情况下，最好在表名上使用混叠。

SELECT junctrans.id, 
       trans.transliteration AS transliteration_id, 
       mean.meaning AS meaning_id, 
       typ.word_type AS word_type_id 
FROM 
  junc_transliteration_meaning_word_type AS junctrans
JOIN junc_meaning_word_type AS juncmean 
  ON juncmean.id = junctrans.meaning_word_type_id 
JOIN hgs_transliterations AS trans
  ON trans.id = junctrans.transliteration_id 
JOIN hgs_meaning AS mean 
  ON mean.id = juncmean.meaning_id 
JOIN hgs_word_types AS typ 
  ON typ.id = juncmean.word_type_id