EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 600+ Courses All in One Bundle
  • Login
Home Software Development Software Development Tutorials Spring Tutorial Spring Boot Query
Secondary Sidebar
Spring Tutorial
  • Spring Boot
    • What is Spring Boot
    • Spring Boot flyway
    • Spring Boot framework
    • Spring Boot Logback
    • Spring Boot actuator endpoints
    • Spring Boot gRPC
    • Spring Boot jdbctemplate example
    • Spring Boot ehcache
    • Spring Boot Architecture
    • Spring Boot Port
    • Introduction of spring boot
    • Spring Boot ide
    • Spring Boot Netty
    • Spring Boot ORM
    • Spring Boot Versions
    • Spring Boot JUnit
    • Spring Boot Keycloak
    • Spring Boot gradle
    • Spring Boot Lombok
    • Spring Boot autowired
    • Spring Boot bean
    • Spring Boot hibernate
    • Spring Boot integration test
    • Spring Boot jdbc
    • Spring Boot MongoDB
    • Spring Boot postgresql
    • Spring Boot rest
    • Spring Boot swagger
    • Spring Boot thymeleaf
    • Spring Boot Unit Test
    • Spring Boot Webflux
    • Spring Boot webclient
    • Spring Boot kubernetes
    • Spring Boot Properties
    • Spring Boot Validation
    • Spring Boot Feature
    • Spring Boot Application
    • Spring Boot email
    • Spring Boot MVC
    • Spring Boot Exception Handling
    • Spring Boot Starter Parent
    • Spring Boot Docker
    • Spring Boot Logging
    • Spring Boot Query
    • Spring Boot Multiple Data Sources
    • Spring Boot Basic Authentication
    • Spring Boot Test
    • Spring Boot jwt
    • Spring Boot Liquibase
    • Spring Boot Prometheus
    • Spring Boot debug
    • Spring Boot GraalVM
    • Spring Boot Batch
    • Spring Boot controller
    • Spring Boot CLI
    • Spring Boot file upload
    • Spring Boot interceptor
    • Spring Boot Service
    • Spring Boot Configuration
    • Spring Boot Datasource Configuration
    • Spring Boot Annotations
    • Spring Boot Starter We
    • Spring Boot Actuator
    • Spring Boot DevTools
    • Spring Boot Repository
    • Spring Boot Dependencies
    • Spring Boot Path Variable
    • Spring Boot Microservices
    • Spring Boot Run Command
    • Spring Boot application.properties
    • Spring Boot Transaction Management
    • Spring Boot Banner
    • Spring Boot JPA
    • Spring Boot Change Port
    • Spring Boot RestTemplate
    • Spring Boot cors
    • Spring Boot HTTPS
    • Spring Boot OAuth2
    • Spring Boot Profiles
    • Spring Boot Interview Questions
    • Spring Boot filter
    • Spring boot logging level
    • Spring Boot Cache
    • Spring Boot Advantages
    • Spring Boot Scheduler
    • Spring Boot Initializr
    • Spring Boot Maven
    • Spring Boot Admin
    • Spring Boot Tomcat
    • Spring Boot WebSocket
    • Spring Boot Executable Jar
    • Spring Boot CommandLineRunner
    • Spring Boot DataSource
    • Spring Batch Scheduler
    • Spring Batch Example
    • Spring Batch Tasklet
    • Spring Batch Admin
    • Spring Batch
    • Spring Boot Qualifier
    • Spring Boot War
    • Spring Boot Test Configuration
  • Spring
    • What is Spring Framework?
    • Spring Architecture
    • What is Spring Integration?
    • IoC Containers
    • What is AOP?
    • Spring Modules
    • Spring Batch Processing
    • Spring Batch Partitioner
    • Spring Batch Job
    • Spring AOP
    • Spring Expression Language
    • Dependency Injection in Spring
    • Spring Batch Architecture
    • Spring framework Interview Questions
  • Spring Cloud Basics
    • What is Spring Cloud
    • Spring Cloud Contract
    • Spring Cloud Components
    • Spring Cloud Version
    • Spring Cloud Data Flow
    • Spring cloud stream
    • Spring Cloud Dependencies
    • Spring cloud microservices
    • spring cloud gateway
    • Spring Cloud Config
    • Spring Cloud Kubernetes
    • Spring Cloud Sleuth

Related Courses

Spring Boot Certification Course

Spring Framework Course Training

All in One Data Science Course

Spring Boot Query

Spring Boot Query

Introduction to Spring Boot Query

In Spring boot, we have a query provided by the JPA to create the sql query above the method declaration only. This annotation can be used inside the interface, unlike named query in JPA. Named query we have written in the class itself, in order to use both these annotations to deal with the SQL, we have to have JAP dependency in place in the project setup; else, it will give a compile-time error for not finding it. By the use of this query annotation, we can write the custom sql query as well; the value attribute for this query will contain the SQL or JPQL to execute it properly. Here we will see both the annotations in detail because they both use to write a query.

Syntax of Spring Boot Query

As we have seen, query annotations are used to write the sql queries in the spring boot application in order to get the desired result from the database.

Syntax of the of this annotations in order to use it:

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

@Query("your query ")
public return_type method _name();

All in One Software Development Bundle(600+ Courses, 50+ projects)
Python TutorialC SharpJavaJavaScript
C Plus PlusSoftware TestingSQLKali Linux
Price
View Courses
600+ Online Courses | 50+ projects | 3000+ Hours | Verifiable Certificates | Lifetime Access
4.6 (86,818 ratings)

As you can see in the above line of syntax, we have used @Query annotation to make the query, which will retrieve the data from the database.

@Query("SELECT e FROM EMP e WHERE e.city = 2")
List<EMP> getALl();

As you can see in the above line of code, we have written one query using @Query annotation, and also it has given you the proper idea of how we can use this in our application. But we have to make some changes to our code while writing it.

How does Spring Boot Query work?

As we already know, that query is used to write the sql query in spring boot, which help us to retrieve the data from the database. But this annotation comes under the JPA so that we can use this inside the JPARepository interface only. We have some standard definition to use this in the application, which needs to follow in order to make it work. This annotation always returns us the specified entity object from the database; while creating the interface, we mentioned all these necessary details inside it. To use this annotation, we should have JPA dependency in the build file, which will enable us to make the database calls.

Here we will see how we can define this using the @Query annotations in spring-boot:

1. @Query

We can use this annotation inside the interface and above the method of the interface. This method will return the desired result of the sql statement. We can also pass our own parameters to the methods in order to pass them into the sql query itself. First, we will have a look at the simple syntax then we can have a look at the param based query.

2. Simple Query

@Query("SELECT e FROM EMP e WHERE e.city = 2")
List<EMP> get();

Here we are trying to get the list of all employees which falls under the city 2 parameter. But as you can see, we have hard code the value for the city param here. get() is the method name here which will return the list of the employee to the calling service, and when we try to call the repository method, this query will always get executed automatically.

3. Param Based

What if we want to pass any param inside it, we have to use the @Param annotations from jap itself; this annotation will help us to bind the value to the query we have created. But in order to use it, we have to make use of the standard defined by the spring boot framework.

@Query("SELECT e FROM EMP e WHERE e.id =:id ")
EMP getById(@Param("id") String id);

As you can see in the above syntax, we have used the param annotation here to get the parameter from the service and bind it to the query we have. Here we have passed the parameter inside the method using the @Param annotation, which needs the param name to be defined in the small brackets; if we miss this, it will give us the compile-time error. Also, we have one syntax to bind it, ‘=:’ this. This will bind the param with the query value and return the result to us.

4. Use Native Query

We can also write the sql native query by the use of the native keyword inside the @Query syntax only. By the use of it, we can write the sql based on the sql syntax only, which will jpa convert to its untestable form.

@Query(
value = "SELECT e FROM EMP e WHERE e.city = 2",
nativeQuery = true)
List<EMP> get();

Required steps which are needed to perform this:

1. We have to create the spring boot project from scratch; we can use the spring initializer to create it fast.

Follow the below link and fill up the required details.

URL: https://start.spring.io/

2. Now, we have added the required dependency into the build file to make use of the given annotation in the application.

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

3. Create the interface which can contain the query inside it.

import com.scania.coc.core.entity.Co2Contents;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.repository.query.Param;
public interface EMPRepo extends JpaRepository<EMP, Integer> {
@Query("SELECT e FROM EMP e WHERE e.id =:id ")
public EMP findByid(@Param("id") String id);
}

It can contain multiple methods depend upon the requirement.

4. Our main application file should look like below.

import org.springframework.boot.SpringApplication;
@SpringBootApplication
@EnableJpaRepositories("base path ")
public class CocCoreApplication {
public static void main(String[] args) throws IOException {
SpringApplication.run(CocCoreApplication.class, args);
}
}

Here we have to use one more annotation, which is @EnableJpaRepositories this will enable the JPA in the application, and when we run our project, it will identify the repository in the application . Also, we have to mention the base package name of our application inside the bracket; otherwise, the application will not be able to scan the package for a repository, and the code will fail.

5. Run the application, and you will see the below trace of logs on the console of your application.

Output:

Spring Boot Query

Conclusion

A query is easy to use and write, as we have already seen. Then, we need to make the necessary change, or we can say configuration in order to use this while coding. Follow the above steps to make it work.

Recommended Articles

This is a guide to Spring Boot Query. Here we discuss the introduction and how the spring boot query works? For better understanding. You may also have a look at the following articles to learn more –

  1. Maven Repository Spring
  2. Spring Boot DevTools
  3. Spring AOP
  4. Spring Cloud Components
Popular Course in this category
Spring Boot Training Program (2 Courses, 3 Project)
  2 Online Courses |  3 Hands-on Projects |  22+ Hours |  Verifiable Certificate of Completion
4.5
Price

View Course

Related Courses

Spring Framework Training (4 Courses, 6 Projects)4.9
All in One Data Science Bundle (360+ Courses, 50+ projects)4.8
0 Shares
Share
Tweet
Share
Primary Sidebar
Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Live Classes
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Java Tutorials
  • Python Tutorials
  • All Tutorials
Certification Courses
  • All Courses
  • Software Development Course - All in One Bundle
  • Become a Python Developer
  • Java Course
  • Become a Selenium Automation Tester
  • Become an IoT Developer
  • ASP.NET Course
  • VB.NET Course
  • PHP Course

ISO 10004:2018 & ISO 9001:2015 Certified

© 2022 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA
Free Software Development Course

C# Programming, Conditional Constructs, Loops, Arrays, OOPS Concept

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA Login

Forgot Password?

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you

By signing up, you agree to our Terms of Use and Privacy Policy.

Let’s Get Started

By signing up, you agree to our Terms of Use and Privacy Policy.

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

Loading . . .
Quiz
Question:

Answer:

Quiz Result
Total QuestionsCorrect AnswersWrong AnswersPercentage

Explore 1000+ varieties of Mock tests View more