MongoDB查询以查找其数组包含一个字符串的文档，该字符串是特定单词的子字符串
对于此类评估，请aggregate()在MongoDB中使用。让我们创建一个包含文档的集合-
> db.demo90.insertOne(
... {"words": ["john", "jace"]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2c1ada79799acab037af56")
}
> db.demo90.insertOne(
... {"words": ["sam", "adam"]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e2c1adb79799acab037af57")
}在find()方法的帮助下显示集合中的所有文档-
> db.demo90.find();
这将产生以下输出-
{ "_id" : ObjectId("5e2c1ada79799acab037af56"), "words" : [ "john", "jace" ] }
{ "_id" : ObjectId("5e2c1adb79799acab037af57"), "words" : [ "sam", "adam" ] }以下是查找文档的查询，该文档的数组包含一个字符串，该字符串是特定单词的子字符串-
> db.demo90.aggregate([ { $match: { $expr: { $anyElementTrue: { $map: { input: "$words", as: "j", in: { $ne: [ -1, { $indexOfBytes: [ "john", "$$j" ] } ] } } } } } } ]);这将产生以下输出-
{ "_id" : ObjectId("5e2c1ada79799acab037af56"), "words" : [ "john", "jace" ] }