在MongoDB中合并两个数组字段？
要合并，请使用$setUnion运算符。首先让我们创建一个包含文档的集合-
> db.mergeTwoArrayFieldDemo.insertOne({"NaturalNumbers":[1,2,3,8,10,20,30],"WholeNumbers":[0,1,2,63,78,20,45]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd68e4057806ebf1256f11d")
}以下是在find()方法的帮助下显示集合中所有文档的查询-
> db.mergeTwoArrayFieldDemo.find().pretty();
这将产生以下输出-
{
"_id" : ObjectId("5cd68e4057806ebf1256f11d"),
"NaturalNumbers" : [
1,
2,
3,
8,
10,
20,
30
],
"WholeNumbers" : [
0,
1,
2,
63,
78,
20,
45
]
}以下是在MongoDB中合并两个数组字段的查询。
> db.mergeTwoArrayFieldDemo.aggregate([
{ "$project": {
"MergedArray": { "$setUnion": [ "$NaturalNumbers", "$WholeNumbers" ] }
}}
]);这将产生以下输出-
{ "_id" : ObjectId("5cd68e4057806ebf1256f11d"), "MergedArray" : [ 0, 1, 2, 3, 8, 10, 20, 30, 45, 63, 78 ] }