如何在 Cloud Firestore 中使用逻辑 OR 执行复合查询? [英] How to perform compound queries with logical OR in Cloud Firestore?

问题描述

来自文档:

您还可以链接多个 where() 方法来创建更具体的查询(逻辑 AND).

You can also chain multiple where() methods to create more specific queries (logical AND).

如何执行 OR 查询?示例:

How can I perform an OR query? Example:

1. 给我字段 status 为 open 或 upcoming
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2. 给我字段 status == open 或 createdAt <= <somedatetime>
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1. Give me all documents where the field status is open OR upcoming
2. Give me all documents where the field status == open OR createdAt <= <somedatetime>

推荐答案

OR 不受支持，因为服务器很难对其进行扩展(需要将状态保持为重复数据删除).解决方法是发出 2 个查询，每个条件一个，并在客户端上进行重复数据删除.

OR isn't supported as it's hard for the server to scale it (requires keeping state to dedup). The work around is to issue 2 queries, one for each condition, and dedup on the client.

编辑(2019 年 11 月):

Cloud Firestore 现在支持 IN 查询，这是一种有限类型的 OR 查询.

Cloud Firestore now supports IN queries which are a limited type of OR query.

对于上面的例子，你可以这样做:

For the example above you could do:

// Get all documents in 'foo' where status is open or upcmoming
db.collection('foo').where('status','in',['open','upcoming']).get()

但是，仍然无法执行涉及多个字段的通用 OR 条件.

However it's still not possible to do a general OR condition involving multiple fields.

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