mongodb使用$ in查询多个对 [英] mongodb query multiple pairs using $in

问题描述

我有一个包含数据的集合names(省略了_id):

I have a collection names with data (_id is omitted):

{first:"John", last:"Smith"},
{first:"Alice", last:"Johnson"},
{first:"Bob", last:"Williams"},
...

和{first, last}是唯一索引.

我想在names中找到很多名字，例如:

I want to find a lot of names in names like:

db.names.find({$or: [{first:"Alice", last:"Brown"}, {first:"Bob", last:"White"}, ...]}

我可以使用$in代替$or来简化此查询吗?

Can I use $in instead of $or to simplify this query?

===

我在MySQL中知道以下查询:

I know in MySQL this following query:

SELECT * FROM names WHERE (first = 'Alice' AND last = 'Brown') OR (first = 'Bob' AND last = 'White') OR ...

可以简化为:

SELECT * FROM names WHERE (first, last) IN (('Alice', 'Brown'), ('Bob','White') OR ...)

但是我无法在MongoDB中找到等效的查询语法.

But I am unable to find the equivalent query syntax in MongoDB.

推荐答案

对此mysql查询

SELECT * FROM names 
WHERE (first = 'Alice' AND last = 'Brown') 
OR (first = 'Bob' AND last = 'White') 
OR ...

可以在mongodb中用作

can be use in mongodb as

db.names.find({
  $or: [
    { first: "Alice", last: "Brown" },
    { first: "Bob", last: "White" }, 
    ...
]})

对于下面的mysql查询

For below mysql query

SELECT * FROM names 
WHERE (first, last) IN (('Alice', 'Brown'), ('Bob','White') OR ...)

您不能创建mongodb $ in 查询

You can not create mongodb $in query

db.names.find({
  $or: [
    { first: { $in: ["John", "Alice", "Bob"] } },
    { last: { $in: ["Smith", "Johnson", "Williams" ] } },
]})

因为它也通过了此结果

("John", "Johnson"),("John", "Williams"),("John", "Smith"),("John", "Williams")..

最好的方法是 $ or ，如问题

db.names.find({ 
  $or: [
    { first: "Alice", last: "Brown" }, 
    { first: "Bob", last: "White" },
     ...
]})

可能是更好的解决方案.如果有的话，我将更新我的答案.谢谢

May be better solution present out there. I will update my answer if find any. Thanks

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