Brug af samlet at håndtere dette spørgsmål fuldstændigt er en smerte.
Men det kan nås.
(MongoDB V2.6+ påkrævet)
var proj1 = {
"$project" : {
"created" : 1,
"_id" : 0,
"h" : {
"$hour" : "$created"
},
"m" : {
"$minute" : "$created"
},
"s" : {
"$second" : "$created"
},
"ml" : {
"$millisecond" : "$created"
}
}
};
var proj2 = {
"$project" : {
"created" : {
"$subtract" : [ "$created", {
"$add" : [ "$ml", {
"$multiply" : [ "$s", 1000 ]
}, {
"$multiply" : [ "$m", 60, 1000 ]
}, {
"$multiply" : [ "$h", 60, 60, 1000 ]
} ]
} ]
}
}
};
var group1 = {
$group : {
_id : "$created",
count : {
$sum : 1
}
}
};
var group2 = {
$group : {
_id : 0,
origin : {
$push : "$$ROOT"
},
maxDate : {
$max : "$_id"
}
}
};
var step = 24 * 60 * 60 * 1000; // milliseconds of one day
var project3 = {
$project : {
origin : 1,
extents : {
$map : {
"input" : [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29],
"as" : "e",
"in" : {
_id : {
$subtract : [ "$maxDate", {
$multiply : [ step, "$$e"]
}]
},
count : {
$add : [0]
}
}
}
}
}
};
var project4 = {
$project : {
_id : 0,
values : {
$setUnion : [ "$origin", "$extents"]
}
}
};
var unwind1 = {
$unwind : "$values"
};
var group3 = {
$group : {
_id : "$values._id",
count : {
$max : "$values.count"
}
}
};
db.product.aggregate([ proj1, proj2, group1, group2, project3, project4,
unwind1, group3, {
$sort : {
_id : 1
}
} ]);
Jeg vil gerne udfylde den manglende del ved ansøgningens afslutning, noget som dette til din reference:
function sortResult(x, y) {
var t1 = x._id.getTime();
var t2 = y._id.getTime();
if (t1 < t2) {
return -1;
} else if (t1 == t2) {
return 0;
} else {
return 1;
}
}
var result = db.product.aggregate();
var endDateMilliseconds = result[result.length - 1]._id.getTime();
var step = 24 * 60 * 60 * 1000; // milliseconds of one day
var map = {};
for (var i in result) {
map[ result[i]._id.getTime() ] = result[i];
}
for (var ms = endDateMilliseconds, x = 1; x < 30; x++) {
ms -= step;
if ( ! ( ms in map ) ) {
map[ms] = {_id : new Date(ms), count : 0};
}
}
var finalResult = [];
for (var x in map) {
finalResult.push(map[x]);
}
finalResult.sort(sortResult);
printjson(finalResult);