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Databases

Gurdeep singh
Gurdeep singh
1,522 Points
Posted by Gurdeep singh
Gurdeep singh
1,522 Points

CAN WE USE JOINS IN SUBQUERY?

I Have a task to Generate a report that lists the book titles from both locations and count the total number of books with the same title.

Can we use union in subqureries SELECT * FROM books_north LEFT OUTER JOIN (LEFT OUTER JOIN loans_north ON books_north.id = loans_north.book_id UNION ALL SELECT * FROM books_south LEFT OUTER JOIN loans_south ON books_south.id = loans_south.book_id) AS t;

1 Answer

Steven Parker
Steven Parker
231,271 Points
Steven Parker
Steven Parker
231,271 Points

Technically, a subquery is used in a WHERE clause and a derived table is used in a FROM clause. But sure, you can use UNIONs and JOINs in either of them.

However, if all you're interested in are the book titles, you can simply this query a good bit by not joining the "loans" table. And it sounds like you might need the COUNT function in there.

Gurdeep singh
Gurdeep singh
1,522 Points
Gurdeep singh
Gurdeep singh
1,522 Points

Yes I need a count thank you I am really stuck on this and also on this topic