mongodb 查找值不为空的文档
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Find documents where value is not null
提问by Jase Whatson
I have the following doc structure
我有以下文档结构
{
"model" : {
},
"_id" : ObjectId("538df963d1c3f82329000257"),
"email" : "[email protected]",
"name" : "sam",
"endpointarn" : "arn:aws:sns:us-east-1:284585229836:endpoint/GCM/Positivethinking/59eb7c66-c13c-3e44-af80-0b1f4f7ea9fd",
"devregidtoken" : "APA91bFMOBo6ZWemMAG5clKEd5VYVvbeDOM5zNXjbbl3faSE0FZt3gtJYv0hpjdWuOY-mvr-k3sCcq0dEveCM6jx5mOh1u6JEubuUmKb2zU64dn_A4gJ4pCBG7AGQJ8DnkO83Ca4wgzsoJcio9T-TtA",
"topicsubs" : [
{
"topicsubid" : "arn:aws:sns:us-east-1:284585229836:Wealth-ProsperityQuotes:5f3e8060-48fa-4a8e-bdc3-e9596747da1a",
"topicname" : "Wealth-Prosperity",
"topicno" : 0
}
],
"timecreated" : ISODate("2014-06-03T16:35:47.442Z"),
"purchasedata" : {
"orderid" : "111",
"packagename" : "",
"productid" : "",
"purchasetime" : "",
"purchasestate" : "",
"developerpayload" : "",
"purchasetoken" : ""
},
"ccode" : "",
"ccodestat" : ""
}
I want to get all documents where purchasedata.orderid IS NOT NULL. I have tried
我想获取purchasedata.orderid 不是NULL 的所有文档。我试过了
db.User.find({"purchasedata.orderid" : {$ne : ""}});
回答by Christian P
If you're checking for nullyou can use $neoperator:
如果您正在检查，null您可以使用$ne运算符：
db.User.find({
"purchasedata.orderid" : { $ne : null }
});
Note:
笔记：
OP originally wanted to check that the value is not an empty string "" and not null. nulland empty string are two different BSON types. You can use $typeand $notoperators to check where the value is nulland that the key exists:
OP 最初想检查该值是否为空字符串 "" 且不为 null。null和空字符串是两种不同的BSON 类型。您可以使用$type和$not运算符来检查值在哪里null以及键是否存在：
db.User.find({
"purchasedata.orderid" : {
$not : { $type : 10 },
$exists : true
}
});
The $typeoperator selects documents where the value is a specific BSON type (10corresponds to Null). $existswill check that the key exists in the subdocument.
在$type操作者选择文件，其中的值是一个特定类型的BSON（10相当于Null）。$exists将检查该键是否存在于子文档中。
回答by vintastic
You were very close. If the value is actually null, you can just use "null" instead of blank.
你非常接近。如果该值实际上为 null，则可以使用“null”而不是空白。
db.User.find({"purchasedata.orderid" : {$ne : null}});
回答by Jase Whatson
So this is what finally worked for me
所以这就是最终对我有用的东西
db.User.find({
"purchasedata.orderid" : {
$exists : true,
$ne : ""
}
});
@Christian p was close so I up voted, but I think my problem was the value wasn't null but actually a empty string, also checking if the value exists is important
@Christian p 很接近所以我投了票，但我认为我的问题是该值不是 null 而实际上是一个空字符串，检查该值是否存在也很重要
