GROUP BY and HAVING

Querity supports GROUP BY and HAVING clauses for aggregate queries. Use advancedQuery() with groupBy to group results and having to filter groups.

Basic GROUP BY

import static io.github.queritylib.querity.api.Querity.*;

// Group by single property
AdvancedQuery query = Querity.advancedQuery()
    .select(selectBy(
        prop("category"),
        count(prop("id")).as("itemCount"),
        sum(prop("amount")).as("totalAmount")
    ))
    .groupBy("category")
    .build();
List<Map<String, Object>> results = querity.findAllProjected(Order.class, query);
// Returns: [{category: "Electronics", itemCount: 42, totalAmount: 15000}, ...]

Group by multiple properties

AdvancedQuery query = Querity.advancedQuery()
    .select(selectBy(
        prop("category"),
        prop("region"),
        avg(prop("price")).as("avgPrice")
    ))
    .groupBy("category", "region")
    .build();

Group by with HAVING clause

AdvancedQuery query = Querity.advancedQuery()
    .select(selectBy(
        prop("category"),
        sum(prop("amount")).as("total")
    ))
    .groupBy("category")
    .having(filterBy(sum(prop("amount")), GREATER_THAN, 1000))
    .build();
// Returns only categories with total amount > 1000

Group by with function expressions

// Group by function result (e.g., group by uppercase category)
AdvancedQuery query = Querity.advancedQuery()
    .select(selectBy(
        upper(prop("category")).as("upperCategory"),
        count(prop("id")).as("orderCount")
    ))
    .groupBy(upper(prop("category")))
    .build();

Backend support:

• JPA: Full support for GROUP BY and HAVING
• MongoDB: Not yet supported
• Elasticsearch: Not supported