在我的产品系列中,我可以找到所有已在“GB”区域发布的产品:
> db.products.find({'release.region':'GB'}).pretty();
{
"_id" : "foo",
"release" : [
{
"region" : "GB",
"date" : ISODate("2012-03-01T00:00:00Z")
},
{
"region" : "US",
"date" : ISODate("2012-09-01T00:00:00Z")
}
]
}
{
"_id" : "bar",
"release" : [
{
"region" : "FR",
"date" : ISODate("2010-07-01T00:00:00Z")
},
{
"region" : "GB",
"date" : ISODate("2012-05-01T00:00:00Z")
}
]
}
{
"_id" : "baz",
"release" : [
{
"region" : "GB",
"date" : ISODate("2011-05-01T00:00:00Z")
},
{
"region" : "NZ",
"date" : ISODate("2012-02-01T00:00:00Z")
}
]
}
如何使用GB发布日期按升序日期顺序对结果进行排序? (例如,订单应该是baz,foo,bar)
注意,我无法在客户端进行排序。
或者,我怎样才能更好地组织数据以实现这一目标。
编辑:我更改了“bar”的FR发布日期,以说明vivek的解决方案不正确。
答案 0 :(得分:2)
因为除了“GB”区域之外,您不需要release
个元素,所以可以使用aggregate
这样做:
db.products.aggregate(
// Filter the docs to just those containing the 'GB' region
{ $match: {'release.region': 'GB'}},
// Duplicate the docs, one per release element
{ $unwind: '$release'},
// Filter the resulting docs to just include the ones from the 'GB' region
{ $match: {'release.region': 'GB'}},
// Sort by release date
{ $sort: {'release.date': 1}})
输出:
{
"result": [
{
"_id": "baz",
"release": {
"region": "GB",
"date": ISODate("20110501T00:00:00Z")
}
},
{
"_id": "foo",
"release": {
"region": "GB",
"date": ISODate("20120301T00:00:00Z")
}
},
{
"_id": "bar",
"release": {
"region": "GB",
"date": ISODate("20120501T00:00:00Z")
}
}
],
"ok": 1
}