对于这种特定情况,一切正常,除非是字段field1,field2请求,并且field1是其中的一部分field2.
示例:
> db.mycoll.findOne()
{
"_id" : 1,
"data" : {
"amounts" : {
"dollar" : 20,
"euro" : 18
},
"item" : "toy",
"sale" : false
}
}
// works well
> db.mycoll.findOne({"_id":1},{ "data.amounts.dollar":1 })
{ "_id" : 1, "data" : { "amounts" : { "dollar" : 20 } } }
// here "data" is root of "data.amounts.dollar" and "data.amounts.euro"
// takes preference, how to query for "data", so
// that all subfields of data are
// returned
> db.mycoll.findOne({"_id":1},{ "data":1 , "data.amounts.dollar":1 })
{ "_id" : 1, "data" : { "amounts" : { "dollar" : 20 } } }
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预期产量:
{
"_id" : 1,
"data" : {
"amounts" : {
"dollar" : 20,
"euro" : 18
},
"item" : "toy",
"sale" : false
}
}
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是的,可以在程序端格式化子字段,并将根字段发送到mongodb查询,但我的问题是如果在没有Javascript的查询方面这是可行的.
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