如何在MongoDB中查找字段为NaN的所有文档？
要在MongoDB中查找字段为NAN的所有文档，请使用以下语法
db.yourCollectionName.find( { yourFieldName: NaN })首先让我们创建一个包含文档的集合
> db.nanDemo.insertOne({"Score":0/0});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca251a26304881c5ce84b8a")
}
> db.nanDemo.insertOne({"Score":10/5});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca2520e6304881c5ce84b8b")
}
> db.nanDemo.insertOne({"Score":20/0});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca252156304881c5ce84b8c")
}
> db.nanDemo.insertOne({"Score":0/20});
{
"acknowledged" : true,
"insertedId" : ObjectId("5ca2521e6304881c5ce84b8d")
}以下是在find()方法的帮助下显示集合中所有文档的查询
> db.nanDemo.find().pretty();
这将产生以下输出
{ "_id" : ObjectId("5ca251a26304881c5ce84b8a"), "Score" : NaN }
{ "_id" : ObjectId("5ca2520e6304881c5ce84b8b"), "Score" : 2 }
{ "_id" : ObjectId("5ca252156304881c5ce84b8c"), "Score" : Infinity }
{ "_id" : ObjectId("5ca2521e6304881c5ce84b8d"), "Score" : 0 }以下是在MongoDB中查找字段为NAN的所有文档的查询
> db.nanDemo.find( { Score: 0/0 });这将产生以下输出
{ "_id" : ObjectId("5ca251a26304881c5ce84b8a"), "Score" : NaN }备用查询如下
> db.nanDemo.find( { Score: NaN })这将产生以下输出
{ "_id" : ObjectId("5ca251a26304881c5ce84b8a"), "Score" : NaN }