这是数据
[ {
"_id": "5c75802b1312ca10e63d2ca7",
"external_user_id": "5cbc86081e06c111f9b16fbf"
},
{
"_id": "5c75a35a3cd9af224c0622c1",
"external_user_id": "5cbc86081e06c111f9b16fbf"
},
{
"_id": "5c82c3bede451c0fd74e6739",
"external_user_id": "5cbc86081e06c111f9b16fd5"
},
{
"_id": "5c85432c1a515a17f2d7a2e7",
"external_user_id": "5cbc86081e06c111f9b16fbc"
},
{
"_id": "5c8e8132bfda140998c2f1c4",
"external_user_id": "5cbc86081e06c111f9b16fbf"
}]
我希望对mongodb进行类似的查询,根据以下查询将不同的文档字段转换为一个字段数组:
{
external_user_id: ["5cbc86081e06c111f9b16fbc", "5cbc86081e06c111f9b16fbf", "5cbc86081e06c111f9b16fd5"]
}
答案 0 :(得分:0)
您可以使用以下汇总
db.collection.aggregate([
{ "$group": {
"_id": null,
"external_user_id": {
"$addToSet": "$external_user_id"
}
}}
])