$ nin与$ expr [英] $nin with the $expr
本文介绍了$ nin与$ expr的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个查询来查找用户CreatedBy是否在SharedWith中.我想反查询，以检查CreatedBy是否不在SharedWith中.
I have a query to find if a user CreatedBy is in a SharedWith. I want to inverse the query to check if the CreatedBy is not in SharedWith.
[
{
"$match": {
"$and": [
{
"$and": [
{
"SharedWith": {
"$exists": true
}
},
{
"$expr": {
"$in": [
"$CreatedBy",
"$Multi_User"
]
}
}
]
}
]
}
}
]
MongoDB不支持直接对$and进行查询的$nin或$not.
MongoDB does not support a direct $nin or $not for $and query.
任何想法如何实现这一目标.
Any idea how to achieve this.
用户文档如下所示，
Collection = [
{"CreatedBy":
{"_id": "User001",
"Email": "user@eg.com",
"Name": "User001"},
"SharedWith": [
{"_id": "User001",
"Email": "user@eg.com",
"Name": "User001"},
{"_id": "User002",
"Email": "user@eg.com",
"Name": "User002"},
{"_id": "User003",
"Email": "user@eg.com",
"Name": "User003"},
]}
]
推荐答案
$nin 是查询运算符，不是聚合运算符，也是 $expr 仅支持aggregation运算符，而不支持query运算符.因此，您可能应该使用 $not $in 使用 $expr 表达式
以这种方式
$nin is an query operator not an aggregation operator and also $expr only supports the aggregation operators not the query ones. So, You should probably use $not $in with the $expr expression
in this manner
{
"$match": {
"$and": [
{
"$or": [
{
"Multi_User": {
"$exists": False
}
},
{
"$expr": {
"$not": { "$in": ["$CreatedBy", "$Multi_User"] }
}
}
]
}
]
}
}
这篇关于$ nin与$ expr的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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