mysql - 查询结果作为条件与另一张表进行条件查询，并且作为其他表查询条件的结果也在最终的结果集出现

Answer 1

select c from C inner join ( select b from B inner join select a  from A on B.b=A.a )  on C.c= B.b;

分割线............

select A.a,B.b,C.c from (select c   from  C where c-column= (select b from B where  b-column = (select a  from A ));

The former is an inner koin connection query, and the latter is a from subquery.
Recommend the former.

I haven’t tried both pieces of code, maybe they are written incorrectly. Any advice is welcome