Mongodb 如何在mongo聚合管道中实现sql子查询?
从表1中选择姓名、年龄,其中姓名在表1中选择姓名,其中年龄>20Mongodb 如何在mongo聚合管道中实现sql子查询?,mongodb,in-subquery,Mongodb,In Subquery,从表1中选择姓名、年龄,其中姓名在表1中选择姓名,其中年龄>20 如何将上述sql子查询转换为mongo聚合管道?给定以下示例数据: db.collection.insert([ { "name": "Peter", "age": 1 }, { "name": "Peter", "age": 10 }, { "name": "Peter", "age": 100 }, { "name": "Paul", "age": 1 }, { "name": "Mar
如何将上述sql子查询转换为mongo聚合管道?给定以下示例数据:
db.collection.insert([
{ "name": "Peter", "age": 1 },
{ "name": "Peter", "age": 10 },
{ "name": "Peter", "age": 100 },
{ "name": "Paul", "age": 1 },
{ "name": "Mary", "age": 100 },
])
你能做的是:
db.collection.aggregate({
$group: {
"_id": "$name", // group by name
"docs": { $push: "$$ROOT" } // push all found documents into an array per group
}
}, {
$match: {
"docs.age": { $gt: 5 } // eliminate all records that do not have at least one "age" entry that's greater than 5
}
}, {
$unwind: "$docs" // flatten the group structure into multiple documents again
}, {
$replaceRoot: {
"newRoot": "$docs" // restore original document layout
}
})
…这将产生:
/* 1 */
{
"_id" : ObjectId("59df15f9ad526e347ed9cda0"),
"name" : "Mary",
"age" : 100.0
}
/* 2 */
{
"_id" : ObjectId("59df15f9ad526e347ed9cd9c"),
"name" : "Peter",
"age" : 1.0
}
/* 3 */
{
"_id" : ObjectId("59df15f9ad526e347ed9cd9d"),
"name" : "Peter",
"age" : 10.0
}
/* 4 */
{
"_id" : ObjectId("59df15f9ad526e347ed9cd9e"),
"name" : "Peter",
"age" : 100.0
}
你能给我们一些样品数据吗?以及所需的JSON输出。