需要将2个表及其FK连接到第3个表中

因此，基本上，我正在关注一个教程问题，该问题问我以下内容。我不太确定如何联接不包含其他FK的2个表，它们（即它们的两个FK）都位于第3个表中。我可以得到一些帮助/解释吗？

我的答案

SELECT Forest.Fo_name, Species.Sp_name, Species.Sp_woodtype FROM Forest INNER JOIN Species ON Tree.Tr_species=Tree.Tr_forest WHERE Fo_loc='ARTIC' ORDER BY Fo_name, Sp_name “对于在编码为“ ARTIC”的区域中找到的森林，列出其中找到的森林名称和物种名称以及物种木材类型。消除任何重复，并按森林名称和物种名称对输出进行排序”

种类表

+--------------+------------------+------+--------------------------------+ | Field | Type | Key | Glossary | +--------------+------------------+------+--------------------------------+ | sp_name | C(10) | PK | Species Name | | sp_woodtype | C(10) | | Wood Yielded by tree | | sp_maxht | I | | Max. Height | +--------------+------------------+------+--------------------------------+ 森林表

+--------------+------------------+------+--------------------------------+ | Field | Type | Key | Glossary | +--------------+------------------+------+--------------------------------+ | Fo_name | C(10) | PK | Forest Name | | Fo_size | I | | Forest Area | | Fo_loc | C(10) | | Geographical Area | | Fo_comp | C(10) | | Forest Owner | +--------------+------------------+------+--------------------------------+ 树桌

+--------------+------------------+------+---------------------------------------------+ | Field | Type | Key | Glossary | +--------------+------------------+------+---------------------------------------------+ | Tr_species | C(10) | FK | (FK of species.sp_name | | Tr_forest | C(10) | FK | (FK of forest.fo_name | | Tr_numb | I | PK | Sequence number | | Tr_planted | Date | | Date of planting | | Tr_loc | C(10) | | Forest quadrant | | Tr_parent | I | FK | (FK of tree.numb) procreating tree reference| +--------------+------------------+------+---------------------------------------------+ C（10）＆我分别代表字符（10）和Integer