SQL-当主键为varchar时如何编写查询

我有3张桌子。

拳头表名称是电影,其字段为mid,tiltre,y​​ear,rating,num_votes

第二个表名称是Person,其字段为pid,name,DOB,Gender

第三个表名称是m_cast,其字段为id,mid,pid(mid和pid是此处的外键)

The primary key such as pid, mid etc. are in varchar format. when i am running the query to join all these 3 tables, then it is not working. its showing only column values but not any row values. then i tried using trim function, then jupyter notebook keeps running for hours but doesn't show any output as you can see in screenshotenter image description here.

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