資料結構
網路
RDBMS
作業系統
Java
MS Excel
iOS
HTML
CSS
Android
Python
C 程式設計
C++
C#
MongoDB
MySQL
Javascript
PHP
物理學
化學
生物學
數學
英語
經濟學
心理學
社會科學
時尚研究
法律研究選擇既不存在、為空或為 false 的 MongoDB 中的欄位中的記錄?
你可以使用 $in 運算子來完成此操作。首先讓我們建立一個包含文件的集合。建立包含文件的集合的查詢如下所示 -
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":1,"StudentName":"Larry"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010215705caea966c557f")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":2,"StudentName":"Mike","hasAgeGreaterThanOrEqualTo18":true});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c90106a5705caea966c5580")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":3,"StudentName":"Carol","hasAgeGreaterThanOrEqualTo18":false});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010795705caea966c5581")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":4,"StudentName":"Sam","hasAgeGreaterThanOrEqualTo18":null});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010865705caea966c5582")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":5,"StudentName":"David","hasAgeGreaterThanOrEqualTo18":false});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010945705caea966c5583")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":6,"StudentName":"Chris","hasAgeGreaterThanOrEqualTo18":null});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010a45705caea966c5584")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":7,"StudentName":"Robert","hasAgeGreaterThanOrEqualTo18":true});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010b05705caea966c5585")
}使用 find() 方法顯示集合中的所有文件。查詢如下所示 -
> db.selectMongoDBDocumentsWithSomeCondition.find().pretty();
以下為輸出 -
{
"_id" : ObjectId("5c9010215705caea966c557f"),
"StudentId" : 1,
"StudentName" : "Larry"
}
{
"_id" : ObjectId("5c90106a5705caea966c5580"),
"StudentId" : 2,
"StudentName" : "Mike",
"hasAgeGreaterThanOrEqualTo18" : true
}
{
"_id" : ObjectId("5c9010795705caea966c5581"),
"StudentId" : 3,
"StudentName" : "Carol",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010865705caea966c5582"),
"StudentId" : 4,
"StudentName" : "Sam",
"hasAgeGreaterThanOrEqualTo18" : null
}
{
"_id" : ObjectId("5c9010945705caea966c5583"),
"StudentId" : 5,
"StudentName" : "David",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010a45705caea966c5584"),
"StudentId" : 6,
"StudentName" : "Chris",
"hasAgeGreaterThanOrEqualTo18" : null
}
{
"_id" : ObjectId("5c9010b05705caea966c5585"),
"StudentId" : 7,
"StudentName" : "Robert",
"hasAgeGreaterThanOrEqualTo18" : true
}以下是如何選擇欄位不存在、為空或為 false 的 MongoDB 文件的查詢 -
> db.selectMongoDBDocumentsWithSomeCondition.find({ "hasAgeGreaterThanOrEqualTo18": {$in: [false,null]}}).pretty();以下為輸出 -
{
"_id" : ObjectId("5c9010215705caea966c557f"),
"StudentId" : 1,
"StudentName" : "Larry"
}
{
"_id" : ObjectId("5c9010795705caea966c5581"),
"StudentId" : 3,
"StudentName" : "Carol",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010865705caea966c5582"),
"StudentId" : 4,
"StudentName" : "Sam",
"hasAgeGreaterThanOrEqualTo18" : null
}
{
"_id" : ObjectId("5c9010945705caea966c5583"),
"StudentId" : 5,
"StudentName" : "David",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010a45705caea966c5584"),
"StudentId" : 6,
"StudentName" : "Chris",
"hasAgeGreaterThanOrEqualTo18" : null
}
更新於: 30-7-2019
345 次瀏覽
廣告