我有这样的收藏。
只有少数用户有 sortOrder 字段
[{
"_id": "59ccf78bde3d14019169c105",
"name": "Best FX broker ",
},
{
"_id": "59ccf78bde3d14019169c102",
"name": "Best automated Performance tool ",
"sortOrder": 1,
},
{
"_id": "59ccf78bde3d14019169c104",
"name": "Best Regtech/ reporting solution ",
},
{
"_id": "59ccf78bde3d14019169c106",
"name": "NEW: BEST CRYPTO SERVICE PROVIDER",
"sortOrder": 2,
}]
当我按 sort({"sortOrder": 1}) 排序时，我得到了这个
[{
"_id": "59ccf78bde3d14019169c105",
"name": "Best FX broker ",
},
{
"_id": "59ccf78bde3d14019169c104",
"name": "Best Regtech/ reporting solution ",
},
{
"_id": "59ccf78bde3d14019169c102",
"name": "Best automated Performance tool ",
"sortOrder": 1,
},
{
"_id": "59ccf78bde3d14019169c106",
"name": "NEW: BEST CRYPTO SERVICE PROVIDER",
"sortOrder": 2,
}]
但我需要像这样对集合进行排序(顶部带有字段 sortOrder 的值)
[ {
"_id": "59ccf78bde3d14019169c102",
"name": "Best automated Performance tool ",
"sortOrder": 1,
},
{
"_id": "59ccf78bde3d14019169c106",
"name": "NEW: BEST CRYPTO SERVICE PROVIDER",
"sortOrder": 2,
},
{
"_id": "59ccf78bde3d14019169c105",
"name": "Best FX broker ",
},
{
"_id": "59ccf78bde3d14019169c104",
"name": "Best Regtech/ reporting solution ",
}]
我应该写什么查询来得到这个？
最佳答案
db.collection.aggregate([
{$project : {"_id" : 1, "sortOrder" : 1,"name":1, "sortOrder": { "$ifNull": [ "$sortOrder", ""] }}},
{$sort : {sortOrder : 1}}
])
关于javascript - 仅对现有字段进行排序，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46668131/