Mysql 如何将本机SQL查询转换为java应用程序的jpa查询

您需要创建Book和Author实体并建立映射。 由于您的模式将作者id存储在books表中。。。我假设这里有多对一映射

SELECT b.books_name,b.books_id FROM BOOKS b JOIN AUTHOR a 
ON b.AUTHOR_ID = a.AUTHOR_ID WHERE a.AUTHOR_NAME='WILLIAM';

JPA查询

@Entity
@Table(name="BOOKS")
Class Books {
    @Id
    Integer booksId;
    String booksName;
    @ManyToOne
    @JoinColumn(name="AUTHOR_ID")
    Author author;
    ... more fields
    public Books(Integer booksId, String booksName) {
        this.booksId = booksId;
        this.booksName = booksName;
    }
}

@Entity
@Table(name="AUTHOR")
Class Author {
    @Id
    String authorId;
    String authorName;
    ... more fields
}

@Query（“从图书b中选择新书（b.booksId，b.booksName），其中b.author.authorName='WILLIAM'）
列出findMatchingBooks（）；

提供实体的更多详细信息。比如字段名和mapping.thnks，这很有帮助

@Query("Select new Books(b.booksId, b.booksName) from Books b where b.author.authorName = 'WILLIAM'")
List<Books> findMatchingBooks();