在带有OR条件的MongoDB查询中获取多个文档？
让我们创建一个包含文档的集合-
> db.demo362.insertOne({"ClientName":"John","ClientProject":"School Management System"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e56a77454a481fef8ec7a1c")
}
> db.demo362.insertOne({"ClientName":"David","ClientProject":"Library Management System"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e56a78454a481fef8ec7a1d")
}
> db.demo362.insertOne({"ClientName":"Mike","ClientProject":"Event Tracker"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e56a7a054a481fef8ec7a1e")
}
> db.demo362.insertOne({"ClientName":"Carol","ClientProject":"Hospital Management System"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e56a7b754a481fef8ec7a1f")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo362.find();
这将产生以下输出-
{ "_id" : ObjectId("5e56a77454a481fef8ec7a1c"), "ClientName" : "John", "ClientProject" : "School Management System" }
{ "_id" : ObjectId("5e56a78454a481fef8ec7a1d"), "ClientName" : "David", "ClientProject" : "Library Management System" }
{ "_id" : ObjectId("5e56a7a054a481fef8ec7a1e"), "ClientName" : "Mike", "ClientProject" : "Event Tracker" }
{ "_id" : ObjectId("5e56a7b754a481fef8ec7a1f"), "ClientName" : "Carol", "ClientProject" : "Hospital Management System" }以下是获取多个文档的查询-
> db.demo362.find({$or: [{"ClientName":"John"}, {"ClientProject": "Event Tracker" }]});这将产生以下输出-
{ "_id" : ObjectId("5e56a77454a481fef8ec7a1c"), "ClientName" : "John", "ClientProject" : "School Management System" }
{ "_id" : ObjectId("5e56a7a054a481fef8ec7a1e"), "ClientName" : "Mike", "ClientProject" : "Event Tracker" }