springData JPA mysql 使用变量报错

java代码：
@Query(value = " set @dense_rank \\:= 0; " + " set @ageTemp \\:= -1; \n " + 
   " select age, " + " CASE WHEN @ageTemp = age THEN @dense_rank \n" + 
   " when @ageTemp != age THEN @dense_rank \\:= @dense_rank + 1 \n" + 
   " END AS DENSE_RANK , @ageTemp \\:= age from sys_note t where t.last_name = '1' order by t.age desc", nativeQuery = true)
public List<Object[]> selectBySql();sql放到数据库中能执行成功
控制台报错：
三月 18, 2018 3:03:26 下午 org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
WARN: SQL Error: 1064, SQLState: 42000
三月 18, 2018 3:03:26 下午 org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions
ERROR: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'set @ageTemp := -1; 
  select age,  CASE WHEN @ageTemp = age THEN @dense_rank 
 ' at line 1
org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:171)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:154)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:417)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
at com.sun.proxy.$Proxy25.selectBySql(Unknown Source)
at com.karen.sysuser.service.SysNoteService.selectBySql(SysNoteService.java:45)
at com.karen.sysuser.service.SysNoteService$$FastClassByCGLIB$$494a343b.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:642)
at com.karen.sysuser.service.SysNoteService$$EnhancerByCGLIB$$a6de2b9f.selectBySql(<generated>)
at com.karen.sysuser.test.SpringDataTest.getAllSysNote(SpringDataTest.java:38)
at com.karen.sysuser.test.SpringDataTest.main(SpringDataTest.java:18)
Caused by: org.hibernate.exception.SQLGrammarException: could not extract ResultSet
at org.hibernate.exception.internal.SQLExceptionTypeDelegate.convert(SQLExceptionTypeDelegate.java:82)
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:61)
at org.hibernate.loader.Loader.getResultSet(Loader.java:2040)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1837)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1816)
at org.hibernate.loader.Loader.doQuery(Loader.java:900)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:342)
at org.hibernate.loader.Loader.doList(Loader.java:2526)
at org.hibernate.loader.Loader.doList(Loader.java:2512)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2342)
at org.hibernate.loader.Loader.list(Loader.java:2337)
at org.hibernate.loader.custom.CustomLoader.list(CustomLoader.java:338)
at org.hibernate.internal.SessionImpl.listCustomQuery(SessionImpl.java:1827)
at org.hibernate.internal.AbstractSessionImpl.list(AbstractSessionImpl.java:231)
at org.hibernate.internal.SQLQueryImpl.list(SQLQueryImpl.java:157)
at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:268)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.springframework.orm.jpa.SharedEntityManagerCreator$DeferredQueryInvocationHandler.invoke(SharedEntityManagerCreator.java:328)
at com.sun.proxy.$Proxy28.getResultList(Unknown Source)
at org.springframework.data.jpa.repository.query.JpaQueryExecution$CollectionExecution.doExecute(JpaQueryExecution.java:96)
at org.springframework.data.jpa.repository.query.JpaQueryExecution.execute(JpaQueryExecution.java:61)
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.doExecute(AbstractJpaQuery.java:95)
at org.springframework.data.jpa.repository.query.AbstractJpaQuery.execute(AbstractJpaQuery.java:85)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:323)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
... 14 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'set @ageTemp := -1; 
  select age,  CASE WHEN @ageTemp = age THEN @dense_rank 
 ' at line 1
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3515)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3447)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1951)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2101)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2554)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1761)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1912)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:116)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:56)
... 45 more