hibernate--多表查询

 

多表返回实体

List<Object> resultList = db.query(
                "from Blog as t0,Usertable as t1 where t0.userId=t1.id").list();// HQL的多表查询
        for (int i = 0; i < resultList.size(); i++) {
            Object[] hql_result_arr = (Object[]) resultList.get(i);//取其中一行的查询结果
            //将查询结果分成两半，分别转化为相应的实体
            Blog blog = (Blog) hql_result_arr[0];
            Usertable usertable = (Usertable) hql_result_arr[1];
}

 

 

String hql = "select bg.id as id,bg.groupId as groupId, b.id as businessId,"+" g.name as groupName,b.name as businessName"
+" from Business b, Businessgroup bg, Groups g "
+" where bg.groupId=g.id and bg.businessId=b.id order by bg.groupId asc";
Session session = this.getSession();
Query query = session.createQuery(hql);
query.setFirstResult(start);
query.setMaxResults(limit);
query.setResultTransformer(Transformers.ALIAS_TO_ENTITY_MAP);//这样会把所有查询的列放到一个元素为Map的list中。
return query.list();

//然后遍历list，从map中以列明为键值取出相应的value，再set到po中
for(int i=0; i<list.size(); i++){
map = (Map) list.get(i);
}

 

public List<ArticleInfo> getArticlePage(int start, int limit, List<FilterBean> filterList) { 


String hql = "select new ArticleInfo(article, column.name) " + "from ArticleInfo article, ColumnInfo column where 1 = 1 " + "and article.columnId = column.id ";
 hql = super.setFilterBean(filterList, hql); 
hql = super.orderBy(hql, "article.createDate desc");
 Query query = super.createQuery(filterList, hql); 
query.setFirstResult(start); query.setMaxResults(limit); return query.list(); 

}

 hql 不支持on

List list = baseDao.findBySQL("SELECT MAX(ID) FROM smsserver_out");

Integer maxId = (Integer)list.get(0);

 

List<Map<String, Object>> copyList = null;

StringBuffer copyInfoBuffer = new StringBuffer(500);
copyInfoBuffer.append("SELECT stf.STAFF_ID AS recieverId, stf.STAFF_NAME AS reciever, stf.HANDSET AS phone, dept.DEPARTMENT_ID AS recieverDeptId, CONCAT_WS('丨', dept2.DEPARTMENT_NAME2, dept.DEPARTMENT_NAME) recieverDeptName FROM jso5_jbase.staff stf ")
    .append("LEFT JOIN jso5_jbase.structure stru ON stf.STAFF_ID = stru.ELEMENT_ID ")
    .append("LEFT JOIN jso5_jbase.department dept ON stru.ELEMENT_PARENT_ID = dept.DEPARTMENT_ID ")
    .append("JOIN (SELECT ELEMENT_ID AS ELEMENT_ID2, ELEMENT_PARENT_ID AS ELEMENT_PARENT_ID2 FROM jso5_jbase.structure) stru2 ON dept.DEPARTMENT_ID = stru2.ELEMENT_ID2 ")
    .append("JOIN (SELECT DEPARTMENT_ID AS DEPARTMENT_ID2, DEPARTMENT_NAME AS DEPARTMENT_NAME2 FROM jso5_jbase.department) dept2 ON stru2.ELEMENT_PARENT_ID2 = dept2.DEPARTMENT_ID2 ")
    .append("WHERE INSTR ('" + copyIds + "', stf.STAFF_id)");

String[] jsonField = { "recieverId", "reciever", "phone", "recieverDeptId", "recieverDeptName" };
copyList = baseDao.queryForListMap(jsonField, copyInfoBuffer.toString(), new Object[]{});