QueryDSL generates JPQL instead of SQL for SQLDialect - spring-boot

Question

Trying to get QueryDSL up for native SQL below is the Spring boot POM snippet
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.7</java.version>
<querydsl.version>4.0.1</querydsl.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-validator</artifactId>
</dependency>
<dependency>
<groupId>org.hsqldb</groupId>
<artifactId>hsqldb</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.querydsl</groupId>
<artifactId>querydsl-sql</artifactId>
<version>${querydsl.version}</version>
</dependency>
<dependency>
<groupId>com.querydsl</groupId>
<artifactId>querydsl-sql-codegen</artifactId>
<version>${querydsl.version}</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
.....
<plugin>
<groupId>com.querydsl</groupId>
<artifactId>querydsl-maven-plugin</artifactId>
<version>${querydsl.version}</version>
<executions>
<execution>
<goals>
<goal>export</goal>
</goals>
</execution>
</executions>
<configuration>
<jdbcDriver>org.hsqldb.jdbc.JDBCDriver</jdbcDriver>
<jdbcUrl>jdbc:hsqldb:file:${project.basedir}/db/init;files_readonly=true</jdbcUrl>
<jdbcUser>sa</jdbcUser>
<schemaPattern>PUBLIC</schemaPattern>
<packageName>com.example.domain</packageName>
<targetFolder>${project.basedir}/src/generated/java</targetFolder>
</configuration>
<dependencies>
<dependency>
<groupId>org.hsqldb</groupId>
<artifactId>hsqldb</artifactId>
<version>2.2.4</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.5</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
The code for executing the query
void test() throws Exception {
QCustomer customer = QCustomer.customer;
System.out.println(dataSource.getConnection().getMetaData().getDatabaseProductName());
SQLTemplates dialect = SQLTemplates.DEFAULT;
SQLQuery query = new SQLQuery(dataSource.getConnection(), dialect);
System.out.println(query.from(customer.count()).fetch());
}
The execution results in SQLException as library generates JPQL(or HQL) instead of Native SQL
Exception in thread "main" com.querydsl.core.QueryException: Caught SQLSyntaxErrorException for
from count(CUSTOMER.ID)
at com.querydsl.sql.DefaultSQLExceptionTranslator.translate(DefaultSQLExceptionTranslator.java:50)
at com.querydsl.sql.Configuration.translate(Configuration.java:451)
at com.querydsl.sql.AbstractSQLQuery.fetch(AbstractSQLQuery.java:399)
at com.example.DemoApplication$Test.test(DemoApplication.java:55)
at com.example.DemoApplication.main(DemoApplication.java:36)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Caused by: java.sql.SQLSyntaxErrorException: unexpected token: FROM

Answer 1

We should be using
query.select(customer.count())
.from(customer)
.fetch()
and for QueryDSL 4.X and later(latest version) refer http://www.querydsl.com/static/querydsl/latest/reference/html/ch02s03.html#d0e1145