jpql

问题 I am doing Java EE with MySQL as database and implementing JPA on my codes. I have no problem retrieving the data from MySQL Workbench but when I change my syntax to JPQL's it does not work. For e.g. in MySQL - it works SELECT date_format(s.date,'%Y, %m, %d') from Transactions s; in JPQL - it does not SELECT date_format(s.date,'%Y, %m, %d') from TransactionEntity s; How do i modify to suit the JPA query? Note: in JPQL the following works SELECT s.date from TransactionEntity s; 回答1: SQL

问题 How can i get a single object by using JPA Native query. I did some researches but all give an answer is use "getSingleResult", however it didn't return what i want to get. For example, what should i do if i want to get a count of table in my database and fetch it into a Integer. This code below shows how i get this by using Sessison hibernate: int check = Integer.parseInt((String) sessionF.createSQLQuery("select to_char(count(*)) as count from user_tables where table_name upper('TEST')")

问题 Is it possible to compare LocalDate with LocalDateTime in HQL/JPQL? This is my query of repository method in spring data which should return amount of orders per required dates. The field deliveryDateTime in Order entity has type LocalDateTime . I want to ignore time part and compare only date part. @Query("SELECT new OrderCountPerDate(DATE(o.deliveryDateTime), COUNT(o.id)) FROM Order o WHERE DATE(o.deliveryDateTime) IN :dates GROUP BY DATE(o.deliveryDateTime) ") List<LocalDate>

问题 I have a dependency spring-boot-starter-data-jpa Configuration for JPA is inside application.properties : spring.datasource.url=jdbc:mysql://localhost:3306/db?serverTimezone=UTC spring.datasource.username=name spring.datasource.password=pass ... When I create @Entity: @Entity @Table(name="cats") public class Cat { @Column(name="age") private int age; .... } It works well. When i try to use JPQL : "select cat from Cat cat" Intellij idea emphasizes it and says "Can't resolve symbol Cat" , I

问题 I have a dependency spring-boot-starter-data-jpa Configuration for JPA is inside application.properties : spring.datasource.url=jdbc:mysql://localhost:3306/db?serverTimezone=UTC spring.datasource.username=name spring.datasource.password=pass ... When I create @Entity: @Entity @Table(name="cats") public class Cat { @Column(name="age") private int age; .... } It works well. When i try to use JPQL : "select cat from Cat cat" Intellij idea emphasizes it and says "Can't resolve symbol Cat" , I

问题 I'm looking for a way to cast an entity inside a jpql query. Example: @Entity class Topic { @OneToMany List<AbstractMessage> messages; } @Entity @Inheritance(strategy = InheritanceType.JOINED) abstract class AbstractMessage { String content; } @Entity class MessageType1 extends AbstractMessage { String att1; } @Entity class MessageType2 extends AbstractMessage { Integer att2; } I'm trying to collect all Topic where one or more of its messages have the type MessageType2 and have att2 = 1. Here

问题 I'm looking for a way to cast an entity inside a jpql query. Example: @Entity class Topic { @OneToMany List<AbstractMessage> messages; } @Entity @Inheritance(strategy = InheritanceType.JOINED) abstract class AbstractMessage { String content; } @Entity class MessageType1 extends AbstractMessage { String att1; } @Entity class MessageType2 extends AbstractMessage { Integer att2; } I'm trying to collect all Topic where one or more of its messages have the type MessageType2 and have att2 = 1. Here

问题 I have 3 tables like: A AB B ------------- ------------ --------------- a1 a1,b1 b1 AB is a transition table between A and B With this, my classes have no composition within these two classes to each other. But I want to know that , with a JPQL Query, if any records exist for my element from A table in AB table. Just number or a boolean value is what I need. Because AB is a transition table, there is no model object for it and I want to know if I can do this with a @Query in my Repository

问题 There are 2 entities: Deck and Card. Each Deck contains 8 out of 100 possible Cards. Since each Deck contains more than one Card and the Card can also be part of many different Decks, I joined them by creating a new table called deck_cards. @Data @Entity @Table(name = "cards") public class Card { @Id private Integer id; @NotBlank private String icon; @NotBlank private String name; @ManyToMany(fetch = FetchType.LAZY, cascade = { CascadeType.PERSIST, CascadeType.MERGE }, mappedBy = "cards")

问题 There are 2 entities: Deck and Card. Each Deck contains 8 out of 100 possible Cards. Since each Deck contains more than one Card and the Card can also be part of many different Decks, I joined them by creating a new table called deck_cards. @Data @Entity @Table(name = "cards") public class Card { @Id private Integer id; @NotBlank private String icon; @NotBlank private String name; @ManyToMany(fetch = FetchType.LAZY, cascade = { CascadeType.PERSIST, CascadeType.MERGE }, mappedBy = "cards")