有人能提供如何返回数组子集的建议吗?例如,假设我有一个包含简单_id键和包含对象数组的键的文档集合(类似下面的示例),我想要找到所有符合简单条件的_id和匹配对象:
// campaigns
{
"_id" : "Fred's C25K",
"campaignData" : [
{
"date" : "2015-06-17",
"source" : "nike"
},
{
"date" : "2015-06-17",
"source" : "reebok",
},
{
"date" : "2015-06-12",
"source" : "nike"
},
{
"date" : "2015-06-14",
"source" : "adidas"
},
]
},
{
"_id" : "Mike's Marathon",
"campaignData" : [
{
"date" : "2015-06-17",
"source" : "nike"
}
]
},
{
"_id" : "Jacob's Jamboree",
"campaignData" : [
{
"date" : "2015-06-17",
"source" : "keen"
}
]
}
我希望我的结果包含 _id 和在“2015-06-17”这个日期值下匹配的所有对象。
// GOAL => To generate a result set that looks like:
{
"_id" : "Fred's C25K",
"campaignData" : [
{
"date" : "2015-06-17",
"source" : "nike"
},
{
"date" : "2015-06-17",
"source" : "reebok",
}
]
},
{
"_id" : "Mike's Marathon",
"campaignData" : [
{
"date" : "2015-06-17",
"source" : "nike"
}
]
},
{
"_id" : "Jacob's Jamboree",
"campaignData" : [
{
"date" : "2015-06-17",
"source" : "keen"
}
]
}