How do you add two columns in HQL?I want to do this :

Select principalamount + Interest from person

How do I write it in HQL?

I used the + operator and I get the error :-

ServletContext resource [/WEB-INF/applicationContext.xml]: Initialization of bean failed; nested exception is java.lang.NullPointerException: null
java.lang.NullPointerException
at org.hibernate.dialect.Dialect$3.getReturnType(Dialect.java:93)
at org.hibernate.hql.ast.util.SessionFactoryHelper.findFunctionReturnType(SessionFactoryHelper.java:376)
at org.hibernate.hql.ast.tree.AggregateNode.getDataType(AggregateNode.java:21)
at org.hibernate.hql.ast.tree.BinaryArithmeticOperatorNode.initialize(BinaryArithmeticOperatorNode.java:29)
at org.hibernate.hql.ast.HqlSqlWalker.prepareArithmeticOperator(HqlSqlWalker.java:1018)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.arithmeticExpr(HqlSqlBaseWalker.java:2729)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.expr(HqlSqlBaseWalker.java:1278)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.arithmeticExpr(HqlSqlBaseWalker.java:2719)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:2006)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:1825)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1394)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:553)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:281)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:229)
at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:228)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:160)
at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111)
at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:77)
at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:56)
at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72)
at org.hibernate.impl.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:400)
at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:351)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1218)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.newSessionFactory(LocalSessionFactoryBean.java:800)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.afterPropertiesSet(LocalSessionFactoryBean.java:726)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1059)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:363)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:226)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:147)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:269)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:320)
at org.springframework.web.context.support.AbstractRefreshableWebApplicationContext.refresh(AbstractRefreshableWebApplicationContext.java:134)
at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:246)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:184)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:49)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:3827)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4343)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:823)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:807)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:595)
at org.apache.catalina.core.StandardHostDeployer.install(StandardHostDeployer.java:277)
at org.apache.catalina.core.StandardHost.install(StandardHost.java:832)
at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:625)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:431)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:983)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:349)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1091)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:789)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1083)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:478)
at org.apache.catalina.core.StandardService.start(StandardService.java:480)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:2313)
at org.apache.catalina.startup.Catalina.start(Catalina.java:556)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:287)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:425)

Can anyone help?

Use an alias i.e.

Select p.x + p.y from person p

See the following example from Hibernate reference doc: -