How to Perform Group By and Aggregate Functions Using Hibernate Criteria?

How to Group by and Aggregate with Hibernate Criteria Object

In Hibernate, the Criteria API provides a convenient way to construct database queries. You can use Criteria to perform a wide range of operations, including filtering, sorting, and grouping.

To implement a SQL query like the following using Hibernate Criteria:

SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name <operator> value
GROUP BY column_name

You can use the groupProperty() method and the aggregate functions provided by the Projections class. For example, to find the maximum and sum of a particular column for a given condition, you could write the following Criteria object:

List result = session.createCriteria(SomeTable.class)
                    .add(Restrictions.ge("someColumn", xxxxx))
                    .setProjection(Projections.projectionList()
                            .add(Projections.groupProperty("someColumn"))
                            .add(Projections.max("someColumn"))
                            .add(Projections.sum("someColumn"))
                    ).list();

This Criteria object will produce SQL similar to the following:

SELECT some_column, MAX(some_column), SUM(some_column)
FROM some_table
WHERE some_column >= xxxxx
GROUP BY some_column

You can use this approach to perform complex grouping and aggregation operations with Hibernate Criteria.

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