PostgreSQL 和 Entity Framework Core 3.1 生成包含内联查询/子查询的查询

Question

我有一个基于 PostgreSQL 数据库的 .NET Core / EF Core 3.1 应用程序。我正在寻找客户。目前，我正在两次访问数据库。第一次是为我找到与我的搜索词匹配的所有客户 ID，然后第二次查询检索该客户的所有相关实体并一次性将它们带回来。例如：

按名称和邮政编码获取客户 ID：

customerIds = (from c in loyalty.Customer.AsNoTracking()
                            where c.FirstName.ToLower() == request.CustomerSearchParameters.FirstName.ToLower() &&
                                  c.LastName.ToLower() == request.CustomerSearchParameters.LastName.ToLower()
                            join a in loyalty.Address on c.CustomerInternalId equals a.CustomerInternalId
                            where a.Postcode == request.CustomerSearchParameters.PostCode
                            select c.CustomerInternalId).ToList();

然后获取这些客户 ID 的所有实体。

            var customers = (from c in loyalty.Customer.AsNoTracking()
                             where customerIds.Contains(c.CustomerInternalId)
                    select c)
                .Include(c => c.ContactInformation).AsNoTracking()
                .Include(c => c.Address).AsNoTracking()
                .Include(c => c.MarketingPreferences).AsNoTracking()
                .Include(c => c.ContentTypePreferences).AsNoTracking()
                .Include(c => c.ExternalCards).AsNoTracking().ToList();

这显然会产生两个查询：

第一：

SELECT c.customer_internal_id

FROM customer AS c

INNER JOIN address AS a ON c.customer_internal_id = a.customer_internal_id

WHERE ((LOWER(c.first_name) = @__ToLower_0) AND (LOWER(c.last_name) = @__ToLower_1)) AND (a.postcode = @__request_CustomerSearchParameters_PostCode_2)

然后

SELECT c.customer_internal_id, c.business_partner_id, c.created_date, c.customer_type, c.date_of_birth, c.first_name, c.gender, c.home_store_id, c.home_store_updated, c.last_name, c.loyalty_db_id, c.mca_id, c.status, c.status_reason, c.store_joined, c.title, c.updated_by, c.updated_date, c.updating_store, c0.contact_internal_id, c0.contact_type, c0.contact_value, c0.created_date, c0.customer_internal_id, c0.updated_by, c0.updated_date, c0.updating_store, c0.validated, a.address_internal_id, a.address_line_1, a.address_line_2, a.address_type, a.address_undeliverable, a.address_validated, a.country, a.created_date, a.customer_internal_id, a.postcode, a.region, a.suburb, a.updated_by, a.updated_date, a.updating_store, m.customer_internal_id, m.channel_id, m.created_date, m.opt_in, m.updated_by, m.updated_date, m.updating_store, m.valid_from_date, c1.customer_internal_id, c1.channel_id, c1.type_id, c1.created_date, c1.opt_in, c1.updated_by, c1.updated_date, c1.updating_store, c1.valid_from_date, e.customer_internal_id, e.card_number, e.card_design, e.card_status, e.card_type, e.created_date, e.updated_by, e.updated_date, e.updating_store

FROM customer AS c

LEFT JOIN contact_information AS c0 ON c.customer_internal_id = c0.customer_internal_id

LEFT JOIN address AS a ON c.customer_internal_id = a.customer_internal_id

LEFT JOIN marketing_preferences AS m ON c.customer_internal_id = m.customer_internal_id

LEFT JOIN content_type_preferences AS c1 ON c.customer_internal_id = c1.customer_internal_id

LEFT JOIN external_cards AS e ON c.customer_internal_id = e.customer_internal_id

WHERE c.customer_internal_id IN ('7495c17d-3e53-4808-a991-6c185c4ced7b')

ORDER BY c.customer_internal_id, c0.contact_internal_id, c0.contact_type, a.address_internal_id, m.customer_internal_id, m.channel_id, c1.customer_internal_id, c1.channel_id, c1.type_id, e.customer_internal_id, e.card_number

是否有任何方法通过 EF Core，我可以使用子查询有效地只访问一次数据库？例如

SELECT attribute, 
attribute, 
attribute, 
attribute, 
attribute
FROM TABLE 
LEFT JOIN OTHER TABLE
LEFT JOIN OTHER TABLE
WHERE customer_internal_id IN (
SELECT customer_internal_id from Customer 
WHERE first name = x AND last name = X AND post code = x) 

Answer 1

var customers = (from customer in loyalty.Customer
                    .Include(c => c.ContactInformation)
                    .Include(c => c.Address)
                    .Include(c => c.MarketingPreferences)
                    .Include(c => c.ContentTypePreferences)
                    .Include(c => c.ExternalCards)
                    .AsNoTracking() 
                from address in loyalty.Address.Where(a => a.CustomerInternalId == customer.CustomerInternalId)
                where customer.FirstName.ToLower() == request.CustomerSearchParameters.FirstName.ToLower() 
                  && customer.LastName.ToLower() == request.CustomerSearchParameters.LastName.ToLower()
                  && address.Address.Postcode == request.CustomerSearchParameters.PostCode
                select customer).ToList();