About aggregate

manual

GROUP BY and HAVING clauses

Explains how to use the GROUP BY and HAVING clauses in a JPA/JPQL query.... BY as DISTINCT (no Aggregates) GROUP BY with Aggregate Functions GROUP BY with HAVING Global ... (each group has unique value combination). Aggregate calculations (count, sum, avg, max, min) that are carried out on all ...

 
forum_thread

Performance issues on aggregate query

we are using this aggregate query to collect some data: ... we are using this aggregate query to collect some data: select ...

 
forum_thread

Does aggregate function "greatest" work on entity objects?

do not come to the function "compareTo" @Entity public class ChatHistoryItem extends AbstractObject implements Comparable {     private static final long serialVersionUID = 1L; ... 11:39 Does aggregate function "greatest" work on entity objects? do not come to ...

 
forum_thread

Problem of query With an aggregate function

Hi I would know if this type of query is supported By JPA: select sum(nb1), sum(nb2), sum(nb3) from table If yes I have this methode that return a list of Long: #1 2014-08-22 11:45 Hi I would know if this type of query is supported By JPA: SELECT sum ( nb1 ) , ...

 
forum_thread

Group by: list if no aggregate function is specified

Hello! In a query like SELECT parent, children FROM Parent parent LEFT JOIN p.children children GROUP BY parent maybe it would be good if it will return a list of Object[2], where the second object is a list of children of a parent. Because creating a query to get a list of parents, then fetching children list for each parent - not a good idea. Thank you. #1 2015-12-28 17:06 Hello! In a query like SELECT parent, children FROM Parent parent LEFT JOIN p.children children GROUP B ...

 
page

ObjectDB Object Database Features

ObjectDB provides a rich set of features, many of them as the result of supporting the JPA and JDO APIs.... primary keys, derived attributes, grouping queries and aggregate queries) which are usually missing from Object Oriented Databases are ... Indices are also used for fast ordering and aggregate calculations . ...

 
api-jpa

javax.persistence.criteria.CriteriaBuilder

Used to construct criteria queries, compound selections, expressions, predicates, orderings.(Interface of JPA)

 
api-jpa

sum(x)

Create an aggregate expression applying the sum operation.(Method of javax.persistence.criteria.CriteriaBuilder)

 
api-jpa

count(x)

Create an aggregate expression applying the count operation.(Method of javax.persistence.criteria.CriteriaBuilder)

 
api-jpa

max(x)

Create an aggregate expression applying the numerical max operation.(Method of javax.persistence.criteria.CriteriaBuilder)