Get one certain entity in an JPQL

Question

currently I am working with JPQL to create an BookRepository.

My data structure looks like this:

• One book can have multiple chapters
• One chapter can have multiple quotes

Now I want to find the book, that have no quotes in the last 10% of the pages. My problem is that my program always compares ALL quotes, but I only need the last one to compare.

This is my JPQL:

@Query("SELECT DISTINCT b FROM Book b, Chapter c, Quote q JOIN b.chapters c JOIN c.quotes q WHERE q.pageNumber < (b.pageNumber * 0.9) AND q ORDER BY b.title")

Thank you for your help!

Answer 1

您可以编辑您的 where 子句，如下所示：

WHERE NOT EXISTS (SELECT * FROM q WHERE q.bookId=b.id AND q.pageNumber>(b.pageNumber * 0.9))