查找价格低于特定值的MongoDB记录
要检查价格小于特定值的记录，请使用$lt。让我们创建一个包含文档的集合-
> db.demo728.insertOne({Price:75});
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab413c43417811278f589b")
}
> db.demo728.insertOne({Price:59});
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab414043417811278f589c")
}
> db.demo728.insertOne({Price:79});
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab414543417811278f589d")
}
> db.demo728.insertOne({Price:89});
{
"acknowledged" : true,
"insertedId" : ObjectId("5eab414843417811278f589e")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo728.find();
这将产生以下输出-
{ "_id" : ObjectId("5eab413c43417811278f589b"), "Price" : 75 }
{ "_id" : ObjectId("5eab414043417811278f589c"), "Price" : 59 }
{ "_id" : ObjectId("5eab414543417811278f589d"), "Price" : 79 }
{ "_id" : ObjectId("5eab414843417811278f589e"), "Price" : 89 }以下是根据条件查找记录的查询-
> db.demo728.find({Price:{$lt:80}});这将产生以下输出-
{ "_id" : ObjectId("5eab413c43417811278f589b"), "Price" : 75 }
{ "_id" : ObjectId("5eab414043417811278f589c"), "Price" : 59 }
{ "_id" : ObjectId("5eab414543417811278f589d"), "Price" : 79 }