"HQL" property query, conditional query

Single attribute:

// returns a list of result set attributes, with the same type of attributes in the element type and entity class            List students = Session.createquery ("Select name from Student"). List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (String) Iter.next ();                SYSTEM.OUT.PRINTLN (name);            }

Multiple properties:

// querying multiple properties, returning a collection            of object arrays // The type of the array element is the            same as the property type of the query // The length of the array is the same            as the number of properties queried in select List students = Session.createquery ("Select ID, name from Student"). List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (object[]) iter.next ();                System.out.println (obj[0] + "," + obj[1]);            }

Multiple property queries, returning student:

// you can use HQL to return            student objects // need to provide a constructor function            List students = Session.createquery ("Select New Student (ID, name) from Student"). List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (Student) Iter.next ();                 + "," + Student.getname ());            }

You can use aliases:

// you can use aliases            List students = Session.createquery ("Select S.id, s.name from Student S"). List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (object[]) iter.next ();                System.out.println (obj[0] + "," + obj[1]);            }

Entity Object query:

 //  Returns a collection of student objects  //  can be suddenly select keyword  List students = Session.createquery (" From            Student "). List ();  for  (Iterator iter=students.iterator (); Iter.hasnext ();)                {Student Student  = (Student) Iter.next ();            System.out.println (Student.getname ()); }

 //  Returns a collection of student objects  //  can be added to the SELECT keyword, you can add an alias  List students = Session.createquer            Y ("from Student S"  for  (Iterator iter=students.iterator (); Iter.hasnext ();)                {Student Student  = (Student) Iter.next ();            System.out.println (Student.getname ()); }

// returns a collection            of student objects // If you use Select to query entity objects, you must use an alias            List students = Session.createquery ("Select S from Student S"). List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (Student) Iter.next ();                System.out.println (Student.getname ());            }

Conditional query

// you can spell the string            List students = Session.createquery ("Select S.id, s.name from Student s where s.name like '%0% '"). List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (object[]) iter.next ();                System.out.println (obj[0] + "," + obj[1]);            }

//can I use? Way to pass parameters//index starting from 0, unlike JDBC starting from 1//values can be quoted in single quotes//List students = session.createquery ("Select S.id, s.name from Student s where s.name like?"). List ();//query query = Session.createquery ("Select S.id, s.name from Student s where s.name like?");//query.setparameter (0, "%0%");//List students = query.list (); //method Chain programming, it is recommended to use this kind of wayList students = session.createquery ("Select S.id, s.name from Student s where s.name like?"). Setparameter (0, "%0%"). List ();  for(Iterator iter=students.iterator (); Iter.hasnext ();) {object[] obj=(object[]) iter.next (); System.out.println (obj[0] + "," + obj[1]); }

// parameters can be passed in the form of: parameter names            List students = session.createquery ("Select S.id, s.name from Student s where S.name like:myname")                    . Setparameter ( "MyName",  "%0%")                    . List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (object[]) iter.next ();                System.out.println (obj[0] + "," + obj[1]);            }

//use? The student who 1,2,3,4,5 the school numberList students = session.createquery ("Select S.id, s.name from Student s where s.id in (?,?,?,?,?)"). Setparameter (0, 1). Setparameter (1, 2). Setparameter (2, 3). Setparameter (3, 4). Setparameter (4, 5). List ();  for(Iterator iter=students.iterator (); Iter.hasnext ();) {object[] obj=(object[]) iter.next (); System.out.println (obj[0] + "," + obj[1]); }

// Adopt: The method of parameter name, inquiry student            number is 1,2,3,4,5 List students = session.createquery ("Select S.id, s.name from Student s where S.id in (: IDs)")                    . Setparameterlist ( /c4>New object[]{1, 2, 3, 4, 5})                    . List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (object[]) iter.next ();                System.out.println (obj[0] + "," + obj[1]);            }

// query 2009-08 of the students can call the MySQL date formatting function            List students = session.createquery ("Select S.id, s.name from Student s where Date_format (S.createtime, '%y-%m ') =?" )                    . Setparameter (0,  "2009-08")                    . List ();              for (Iterator iter=students.iterator (); Iter.hasnext ();) {                = (object[]) iter.next ();                System.out.println (obj[0] + "," + obj[1]);            }

SimpleDateFormat SDF =NewSimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"); //For students from 2009-08-01 to 2009-08-20, you can call the MySQL date format functionList students = session.createquery ("Select S.id, s.name from Student s where s.createtime between? and? "). Setparameter (0, Sdf.parse ("2009-08-01 00:00:00"). Setparameter (1, Sdf.parse ("2009-08-20 23:59:59") . List ();  for(Iterator iter=students.iterator (); Iter.hasnext ();) {object[] obj=(object[]) iter.next (); System.out.println (obj[0] + "," + obj[1]); }

"HQL" property query, conditional query