Querydsl在同一表上多次联接

Question

假设我有两个表task和company。company包含id和name列。Task有两列CustomerID和ProviderID，它们链接回Company的ID列。

Configuration configuration = new Configuration(templates);
JPASQLQuery query = new JPASQLQuery(this.entityManager, configuration);

QTask task = QTask.task;
QCompany customer = QCompany.company;
QCompany provider = QCompany.company;

JPASQLQuery sql = query.from(task).join(customer).on(customer.id.eq(task.customerId))
    .join(provider).on(provider.id.eq(task.providerId));

return sql.list(task.id, customer.name.as("customerName"), provider.name.as("providerName"));

select task.id, company.name as customerName, company.name as providerName from task join company on company.id = task.customerId

select task.id, customer.name as customerName, provider.name as providerName from task join company as customer on customer.id = task.customerId join company as provider on provider.id = task.providerId

Answer 1

如果需要to变量，只需执行以下操作

QCompany customer = new QCompany("customer");
QCompany provider = new QCompany("provider");

重新分配默认变量qcompany.company没有帮助