Querydsl变换与分组依据并具有

Question

I have a database table with products and want to find products with the same name via Querydsl

I have something like this:

QProduct product = QProduct.product;
JPAQuery query = new JPAQuery(entityManager);

Map<String, List<Product>> = query.from(product)
            .transform(groupBy(product.name).as(list(product)));

Then I get a Map with Product names as key. To every name key I get a list with products having this name. Since I want to find name duplicates I need product lists greater than 1 only. So I need a where clause with a nested SQL-Statement to ignore products with unique names:

SELECT * FROM Product p1
  WHERE (SELECT COUNT(*) FROM Product p2 WHERE p1.name=p2.name)>1 

How can I include this in the querydsl query above. Or is there another way to limit the product lists in the map to lists greater than 1 only.

Maybe there is a possibility using HAVING COUNT in querydsl?

Thanks, Nick

Answer 1

on the day one year later... someone had (almost) the same issue... and found a solution! =)

the sample below is not a solution to the question but a hint how to get a having statement into transform projection. I hope this helps at least someone! :)

    QStagingData data = QStagingData.stagingData;
    List<StagingDataPlausiProjection> transform = new JPAQuery<>(getEntityManager())
            .select(Projections.bean(StagingDataPlausiProjection.class,
                    data.branch, data.account, data.costCenter, data.receiptMonth))
            .where(data.tenant.eq(tenant).and(data.bookingYear.eq(year)))
            .groupBy(data.branch, data.account, data.costCenter, data.receiptMonth)
            .having(data.value.sum().ne(BigDecimal.ZERO))
            .fetch();