请问 这个hql 查询语句有什么问题么 为什么会报空指针异常呢
from cn.com.FormBean.UserTable as ut inner join cn.com.FormBean.SexTable as st where ut.User_Sex_Id = st.Sex_Id
异常如下 Exception in thread "main" java.lang.NullPointerException
at org.hibernate.hql.ast.HqlSqlWalker.createFromJoinElement(HqlSqlWalker.java:317)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.joinElement(HqlSqlBaseWalker.java:3268)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3060)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:2938)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:688)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:544)
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:218)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:158)
at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:109)
at org.hibernate.engine.query.HQLQueryPlan. <init>(HQLQueryPlan.java:75)
at org.hibernate.engine.query.HQLQueryPlan. <init>(HQLQueryPlan.java:54)
at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:71)
at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133)
at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112)
at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1583)
at cn.com.Dao.TestDao.Selectsth(TestDao.java:61)
at cn.com.Dao.TestDao.main(TestDao.java:75)
from cn.com.FormBean.UserTable as ut inner join cn.com.FormBean.SexTable as st where ut.User_Sex_Id = st.Sex_Id
异常如下 Exception in thread "main" java.lang.NullPointerException
at org.hibernate.hql.ast.HqlSqlWalker.createFromJoinElement(HqlSqlWalker.java:317)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.joinElement(HqlSqlBaseWalker.java:3268)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElement(HqlSqlBaseWalker.java:3060)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromElementList(HqlSqlBaseWalker.java:2938)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.fromClause(HqlSqlBaseWalker.java:688)
at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:544)
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:218)
at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:158)
at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:109)
at org.hibernate.engine.query.HQLQueryPlan. <init>(HQLQueryPlan.java:75)
at org.hibernate.engine.query.HQLQueryPlan. <init>(HQLQueryPlan.java:54)
at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:71)
at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:133)
at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:112)
at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1583)
at cn.com.Dao.TestDao.Selectsth(TestDao.java:61)
at cn.com.Dao.TestDao.main(TestDao.java:75)
要使用联结的话就把where改为On,否则就把两者作为不相关的表,只是筛选出其中字段数据相同的交集数据的话就使用逗号隔开两个表,后面使用where,也就是:
from cn.com.FormBean.UserTable as ut inner join cn.com.FormBean.SexTable as st on ut.User_Sex_Id = st.Sex_Id
或者
from cn.com.FormBean.UserTable as ut,cn.com.FormBean.SexTable as st where ut.User_Sex_Id = st.Sex_Id
使用了未初始化变量~~~- -