如何将本机SQL查询转换为Java应用程序的JPA查询

洛基
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';
Shivangi Gupta

您需要创建Book and Author实体并建立映射。由于您的架构将author_id和books表存储在一起...我假设这里有很多一对一的映射。

@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
}

JPA查询

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

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