如何使用HQL（休眠查询语言）获取列的最后一个值

Question

As shown in the picture, I need the last value of bookingID column using hibernate in MySQL.

@SuppressWarnings("unchecked")
    @Override
    public Booking listBookingsID() {
        Session session = this.sessionFactory.getCurrentSession();
        Booking bookList =  (Booking) session.createQuery("from Booking ORDER BY bookid DESC")
                .setMaxResults(1).uniqueResult();


        return bookList;
    }

I tried that code which is found in this link , but it always shows as "9". If the last value is "1" then it should show as 1, but it's 9.

So my question is: "Are there any queries to get the last value of a column in hibernate?"

Answer 1

You can get the Maximum ID of your table like:

HibernateEntityManager he;

long lastID = ((Number) he.createNativeQuery("select max(id) from table;").getSingleResult()).longValue();

then you can get the bookingID from it with searching for the row with lastID

if you use JPA, it would be like this:

long bookingID;
bookingID = bookRepository.findOne(lastID).getBookingID;

Answer 2

A Database table doesn't have a order itself. So there is no direct way to query for the last entry.

But since your table uses an autoincrement primary key id you can get the last inserted entry by sorting the result by this id in descending order and select the first result

Booking booking =  (Booking) session.createQuery("from Booking ORDER BY id DESC")
            .setMaxResults(1).uniqueResult();

This will get you the Booking with the highest id , now all you have to do is select the bookingId of that entry:

  return booking.getBookingId();

Answer 3

Try this:

Booking bookList =  (Booking) session.createQuery("from Booking ORDER BY bookid DESC")
    .setMaxResults(1).getSingleResult();