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我有以下两个查询集books1 和books2。在两者上，我都使用 annotate 添加另一列，book1 的常数为 10，books2 的常数为 30。问题是在我连接查询集之后，最终集显示注释值 = 10，即使对于 books2

author1 = Author.objects.get(pk=1)

books1 = author1.books_set.annotate(sample_var=Value(10))

author2 = Author.objects.get(pk=2)

books2 = author2.books_set.annotate(sample_var=Value(30))

combine = books1 | books2

我所看到的：

name                  author id       sample_var
name1 (from books1)       1                10
..                        1                10
..                        1                10
..                        1                10
name2 (from books2)       2                10 (instead of 30) 
..                        2                10 (instead of 30) 
..                        2                10 (instead of 30) 
..                        2                10 (instead of 30)

原因是，用于组合的 sql 如下。当我尝试访问 combine[0].name 时，我得到了这个。它负责 WHERE 部分，但不负责注释部分。它使用 10 AS "sample_var" 作为组合查询集，这是不对的，这就是上表中所有显示 10 的原因。

SELECT "books_books"."name", "books_books"."author_id", 10 AS "sample_var"
FROM "books_books" 
WHERE ("books_books"."author_id" = 1 OR "books_books"."author_id" = 2)

我认为如果联合正确发生，sql应该是：

SELECT "books_books"."name", "books_books"."author_id", 10 AS "sample_var"
FROM "books_books" 
WHERE ("books_books"."author_id" = 1)
union all
SELECT "books_books"."name", "books_books"."author_id", 30 AS "sample_var"
FROM "books_books" 
WHERE ("books_books"."author_id" = 2)
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1 回答 1

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在 Django 1.11 中，您可以执行union，在您的情况下：

all_books = books1.union(books2, all=True)
于 2017-09-19T14:51:17.900 回答