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
化學
生物
數學
英語
經濟學
心理學
社會研究
時裝研究
法律研究在使用 MongoDB 的列表查詢中獲得至少一項匹配值？
使用 $in 運算子進行至少一項匹配。我們先建立一個包含文件的集合 −
> db.atleastOneMatchDemo.insertOne({"StudentFavouriteSubject":["MySQL","MongoDB"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd2db5db64f4b851c3a13ce")
}
> db.atleastOneMatchDemo.insertOne({"StudentFavouriteSubject":["Java","C","MongoDB"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd2db71b64f4b851c3a13cf")
}
> db.atleastOneMatchDemo.insertOne({"StudentFavouriteSubject":["Python","C++","SQL Server"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd2db87b64f4b851c3a13d0")
}
>db.atleastOneMatchDemo.insertOne({"StudentFavouriteSubject":["Ruby","Javascript","C#","MySQL"]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd2dba9b64f4b851c3a13d1")
}以下是使用 find() 方法顯示集合中所有文件的查詢 −
> db.atleastOneMatchDemo.find().pretty();
將生成以下輸出 −
{
"_id" : ObjectId("5cd2db5db64f4b851c3a13ce"),
"StudentFavouriteSubject" : [
"MySQL",
"MongoDB"
]
}
{
"_id" : ObjectId("5cd2db71b64f4b851c3a13cf"),
"StudentFavouriteSubject" : [
"Java",
"C",
"MongoDB"
]
}
{
"_id" : ObjectId("5cd2db87b64f4b851c3a13d0"),
"StudentFavouriteSubject" : [
"Python",
"C++",
"SQL Server"
]
}
{
"_id" : ObjectId("5cd2dba9b64f4b851c3a13d1"),
"StudentFavouriteSubject" : [
"Ruby",
"Javascript",
"C#",
"MySQL"
]
}以下是進行至少一項匹配的查詢 −
>db.atleastOneMatchDemo.find({"StudentFavouriteSubject":{"$in":["MongoDB","MySQL"]}}).pretty();將生成以下輸出 −
{
"_id" : ObjectId("5cd2db5db64f4b851c3a13ce"),
"StudentFavouriteSubject" : [
"MySQL",
"MongoDB"
]
}
{
"_id" : ObjectId("5cd2db71b64f4b851c3a13cf"),
"StudentFavouriteSubject" : [
"Java",
"C",
"MongoDB"
]
}
{
"_id" : ObjectId("5cd2dba9b64f4b851c3a13d1"),
"StudentFavouriteSubject" : [
"Ruby",
"Javascript",
"C#",
"MySQL"
]
}
更新於： 2019 年 7 月 30 日
387 次瀏覽
廣告