在具有关系的 Laravel Eloquent 查询构建器中将 UNION 与 DISTINCT 结合使用

Question

我有 2 个 table，

properties
+----+-----------+
| id | parent_id |
+----+-----------+
|  1 | null      |
|  2 | 1         |
|  3 | null      |
|  4 | 3         |
|  5 | 3         |
|  6 | null      |
+----+-----------+

和

sale_services
+----+-------------+------+
| id | property_id | rank |
+----+-------------+------+
|  1 |           2 |    5 |
|  2 |           4 |    4 |
|  3 |           5 |    6 |
|  4 |           6 |    7 |
+----+-------------+------+

通过关系 (sale_service.property_id = property.id)。属性可以链接到同一个属性中的另一个 table.

我需要获取 SaleService 实例的集合，其中相关的 property.parent_id 为 null 或者 sale_services [=78= 中有一些记录] 通过 properties table 共享相同的 parent_id，按该字段区分并按 rank.

排序

结果应该是

+----+-------------+------+
| id | property_id | rank |
+----+-------------+------+
|  1 |           2 |    5 |
|  3 |           5 |    6 |
|  4 |           6 |    7 |
+----+-------------+------+

- sale_services table 中的所有项目，除了 (sale_service.id = 2)，因为它属性共享相同的 parent_id 与项目 (sale_service.id = 3) 和项目与 (sale_service.id = 3) 最高 rank价值

我找到了 SQL 代码来获得想要的结果，

 SELECT *
    FROM
      (SELECT DISTINCT ON (properties.parent_id) *
       FROM "sale_services"
       INNER JOIN "properties" ON "sale_services"."property_id" = "properties"."id"
       WHERE ("properties"."parent_id") IS NOT NULL
       ORDER BY "properties"."parent_id", "sale_services"."rank" DESC) AS sub
    UNION
    SELECT *
    FROM "sale_services"
    INNER JOIN "properties" ON "sale_services"."property_id" = "properties"."id"
    WHERE ("properties"."parent_id") IS NULL

但我无法与 Eloquent Builder 达到相同的水平。

我试过这样的东西

$queryWithParent = SaleService::query()
    ->select(\DB::raw('DISTINCT ON (properties.parent_id) *'))
    ->whereNotNull('properties.parent_id')
    ->join('properties', 'sale_services.property_id', '=', 'properties.id')
    ->orderBy('parent_id')
    ->orderBy('sale_services.index_range', 'desc');

$queryWithoutParent = SaleService::query()
    ->join('properties', 'sale_services.property_id', '=', 'properties.id')
    ->whereNull('properties.parent_id');

$query = $queryWithParent->union($queryWithoutParent);

但出现错误

SQLSTATE[42601]: Syntax error: 7 ERROR: syntax error at or near "union" LINE 1: ...perties.type <> 'hotel') order by "parent_id" asc union sele... ^ (SQL: select DISTINCT ON (properties.parent_id) * from "sale_services" inner join "properties" on "sale_services"."property_id" = "properties"."id" where ("properties"."parent_id") is not null and ("sale_services"."deleted_at") is null and "published" = 1 and exists (select 1 from "properties" where properties.id = sale_services.property_id AND properties.type <> 'hotel') order by "parent_id" asc union select * from "sale_services" inner join "properties" on "sale_services"."property_id" = "properties"."id" where ("properties"."parent_id") is null and ("sale_services"."deleted_at") is null and "published" = 1 and exists (select 1 from "properties" where properties.id = sale_services.property_id AND properties.type <> 'hotel') order by "index_range" desc limit 12 offset 0)

如果我从第一个查询中删除排序 ($queryWithParent) 它似乎有效，但在不同的查询中选择了随机项目。

是否有任何其他方法可以达到相同的结果，或者我做错了什么？

Answer 1

"Distinct" 的 laravel 查询创建者是 distinct()，如：

$queryWithParent = SaleService::query()
->distinct('properties.parent_id')
->whereNotNull('properties.parent_id')
->join('properties', 'sale_services.property_id', '=', 'properties.id')
->orderBy('parent_id')
->orderBy('sale_services.index_range', 'desc');

这样行吗？

Answer 2

终于找到解决办法了。

使用Laravel ^5.7.28（UNION 问题已在Laravel 5.7.28: github.com/laravel/framework/pull/27589 中修复），您将不需要子查询！

将table列指定为select以避免列名冲突sale_services.*

$queryWithParent = SaleService::query()
    ->select(\DB::raw('DISTINCT ON (properties.parent_id) sale_services.*'))
    ->from('sale_services')
    ->join('properties', 'sale_services.property_id', '=', 'properties.id')
    ->whereNotNull('properties.parent_id')
    ->orderBy('properties.parent_id')
    ->orderBy('sale_services.index_range', 'desc');

$queryWithoutParent = SaleService::query()
    ->select(\DB::raw('sale_services.*'))
    ->join('properties', 'sale_services.property_id', '=', 'properties.id')
    ->whereNull('properties.parent_id');

$query = $queryWithParent->union($queryWithoutParent);

在具有关系的 Laravel Eloquent 查询构建器中将 UNION 与 DISTINCT 结合使用

Use UNION with DISTINCT in Laravel Eloquent query builder with relations

postgresql

union

distinct

laravel

eloquent