MongoDB中布尔值的语法是什么？
您可以将$eq和$ne运算符用于布尔值。首先让我们创建一个包含文档的集合-
> db.booleanQueryDemo.insertOne({"UserName":"John","UserAge":23,"isMarried":true});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc815c08f9e6ff3eb0ce44a")
}
> db.booleanQueryDemo.insertOne({"UserName":"Chris","UserAge":21,"isMarried":false});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc815d08f9e6ff3eb0ce44b")
}
> db.booleanQueryDemo.insertOne({"UserName":"Robert","UserAge":24,"isMarried":false});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc815dc8f9e6ff3eb0ce44c")
}
> db.booleanQueryDemo.insertOne({"UserName":"David","UserAge":26,"isMarried":true});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cc815ed8f9e6ff3eb0ce44d")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.booleanQueryDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cc815c08f9e6ff3eb0ce44a"),
"UserName" : "John",
"UserAge" : 23,
"isMarried" : true
}
{
"_id" : ObjectId("5cc815d08f9e6ff3eb0ce44b"),
"UserName" : "Chris",
"UserAge" : 21,
"isMarried" : false
}
{
"_id" : ObjectId("5cc815dc8f9e6ff3eb0ce44c"),
"UserName" : "Robert",
"UserAge" : 24,
"isMarried" : false
}
{
"_id" : ObjectId("5cc815ed8f9e6ff3eb0ce44d"),
"UserName" : "David",
"UserAge" : 26,
"isMarried" : true
}情况1-当值等于false时。
以下是布尔值的查询-
> db.booleanQueryDemo.find({isMarried: {$eq: false}}).pretty();这将产生以下输出-
{
"_id" : ObjectId("5cc815d08f9e6ff3eb0ce44b"),
"UserName" : "Chris",
"UserAge" : 21,
"isMarried" : false
}
{
"_id" : ObjectId("5cc815dc8f9e6ff3eb0ce44c"),
"UserName" : "Robert",
"UserAge" : 24,
"isMarried" : false
}情况2-当值等于true时。
以下是查询-
> db.booleanQueryDemo.find({isMarried: {$ne: false}}).pretty();这将产生以下输出-
{
"_id" : ObjectId("5cc815c08f9e6ff3eb0ce44a"),
"UserName" : "John",
"UserAge" : 23,
"isMarried" : true
}
{
"_id" : ObjectId("5cc815ed8f9e6ff3eb0ce44d"),
"UserName" : "David",
"UserAge" : 26,
"isMarried" : true
}