How to Implement a Group-By Query in Hibernate Using Criteria?

Hibernate Group-By Query using Criteria

In this question, a user seeks assistance in implementing an SQL query with Hibernate Criteria. The query involves grouping results based on a column, applying an aggregation function, and filtering records based on a comparison with a value.

To achieve this using Hibernate Criteria, the user can utilize the groupProperty() method on the Criteria object and combine it with the relevant aggregation functions provided by the Projections class. For instance, consider the following SQL query:

SELECT column_name, max(column_name), min(column_name), count(column_name)
FROM table_name
WHERE column_name > xxxxx
GROUP BY column_name

The corresponding Hibernate Criteria object would be:

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

In summary, by incorporating groupProperty() and aggregate functions from Projections, Hibernate Criteria objects provide a powerful mechanism for executing complex group-by queries efficiently.

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