Session session =Session session = super.getSession();

session.flush();

Connection con = session.connection();

String uid="";

StringBuffer sql = new StringBuffer();

sql.append("select a.user_Id from user_info as a");//user用户表

sql.append( left join (select b.userid from B_info as b where b.userid="+uid+"

and ( b.bdate= (select max(bdate) from b_info where userid=b.userid)) )) as binfo on a.user_id=binfo.userid

Statement stmt = (Statement) con.createStatement();

ResultSet rs = stmt.executeQuery(sql.toString());

while(rs.next())

{

uid=rs.getString(1);

}

return uid;

}

?