The result of table A query is used as the condition of table B query.
The result of table B query is used as the condition of table C query.
The final result set consists of the query results of A, B and C tables respectively
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; Parting line ............ 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 join query and the latter is a from subquery.
The former is recommended.
I haven’t tried either of the two pieces of code, which may have been written incorrectly. Welcome to give directions