Native SQL queries in Spring Boot - Step-by-Step Execution

Concept Flow - Native SQL queries

Define Native SQL Query

↓

Annotate Repository Method

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Call Method in Service

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Spring Boot Executes SQL

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Return Results to Service

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Use Results in Application

This flow shows how a native SQL query is defined, linked to a repository method, executed by Spring Boot, and results returned for use.

Execution Sample

Spring Boot

public interface UserRepository extends JpaRepository<User, Long> {
  @Query(value = "SELECT * FROM users WHERE email = ?1", nativeQuery = true)
  User findByEmailNative(String email);
}

Defines a native SQL query in a Spring Data repository to find a user by email.

Execution Table

Step	Action	SQL Query	Parameter	Result
1	Call findByEmailNative("[e-mail]")	SELECT * FROM users WHERE email = ?1	[e-mail]	Query prepared
2	Spring Boot executes native SQL	SELECT * FROM users WHERE email = '[e-mail]'	[e-mail]	Database returns matching user row
3	Spring Boot maps result to User entity	N/A	N/A	User object created with data
4	Return User object to caller	N/A	N/A	User object with email [e-mail]
5	End	N/A	N/A	Method execution complete

💡 Method returns User object or null if no match found

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
email	null	[e-mail]	[e-mail]	[e-mail]	[e-mail]
SQL Query	null	SELECT * FROM users WHERE email = ?1	SELECT * FROM users WHERE email = '[e-mail]'	N/A	N/A
User	null	null	null	User entity with data	User entity with data

Key Moments - 3 Insights

Why do we use nativeQuery = true in the @Query annotation?

Because it tells Spring Boot this is a raw SQL query, not JPQL. See execution_table step 1 where the query is prepared as native SQL.

How does Spring Boot map the SQL result to a User object?

Spring Boot uses the entity mapping defined for User to convert the database row into a User instance, as shown in execution_table step 3.

What happens if no user matches the email?

The query returns no rows, so Spring Boot returns null instead of a User object, ending the method as in execution_table step 5.

Visual Quiz - 3 Questions

Look at the execution_table, what SQL query is executed at step 2?

A SELECT email FROM users

B SELECT * FROM users WHERE email = '[e-mail]'

C SELECT * FROM users WHERE email = ?1

D SELECT * FROM users

💡 Hint

Check the SQL Query column at step 2 in the execution_table.

At which step does Spring Boot create the User object from the database result?

A Step 3

B Step 2

C Step 1

D Step 4

💡 Hint

Look at the Result column describing object creation in the execution_table.

If the email parameter was null, how would the execution_table change?

A Step 1 would fail to prepare the query

B Step 3 would create a User with null email

C Step 2 would execute with email = null and return no user

D Step 4 would return a User object anyway

💡 Hint

Consider how SQL handles null parameters and the flow in execution_table steps 1 and 2.

Concept Snapshot

Native SQL queries in Spring Boot:
- Use @Query annotation with nativeQuery=true
- Write raw SQL inside value attribute
- Method parameters replace SQL placeholders
- Spring Boot executes SQL directly on DB
- Results map to entity objects automatically

Full Transcript

This visual execution shows how native SQL queries work in Spring Boot. First, you define a repository method with @Query and nativeQuery=true. The SQL query uses placeholders for parameters. When the method is called, Spring Boot prepares the SQL with the parameter values, executes it on the database, and gets the result. Then it maps the database row to a User entity object and returns it. If no row matches, it returns null. This process lets you run raw SQL while still using Spring Data repositories.