diff options
Diffstat (limited to 'src/mongo/db/commands/aggregate.js')
| -rwxr-xr-x | src/mongo/db/commands/aggregate.js | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/src/mongo/db/commands/aggregate.js b/src/mongo/db/commands/aggregate.js new file mode 100755 index 00000000000..7741e3121ff --- /dev/null +++ b/src/mongo/db/commands/aggregate.js @@ -0,0 +1,184 @@ +/* sample aggregate command queries */
+
+// make sure we're using the right db; this is the same as "use mydb;" in shell
+db = db.getSisterDB("mydb");
+
+// just passing through fields
+var p1 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ tags : 1,
+ pageViews : 1
+ }}
+]});
+
+// unwinding an array
+var p2 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ tag : { $unwind : "tags" },
+ pageViews : 1
+ }}
+]});
+
+// pulling values out of subdocuments
+var p3 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ otherfoo : "other.foo",
+ otherbar : "other.bar"
+ }}
+]});
+
+// projection includes a computed value
+var p4 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ daveWroteIt : { $eq:["$author", "dave"] }
+ }}
+]});
+
+// projection includes a virtual (fabricated) document
+var p5 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ pageViews : 1,
+ tag : { $unwind : "tags" }
+ }},
+ { $project : {
+ author : 1,
+ subDocument : { foo : "pageViews", bar : "tag" }
+ }}
+]});
+
+// multi-step aggregate
+// nested expressions in computed fields
+var p6 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ tag : { $unwind : "tags" },
+ pageViews : 1
+ }},
+ { $project : {
+ author : 1,
+ tag : 1,
+ pageViews : 1,
+ daveWroteIt : { $eq:["$author", "dave"] },
+ weLikeIt : { $or:[ { $eq:["$author", "dave"] },
+ { $eq:["$tag", "good"] } ] }
+ }}
+]});
+
+// slightly more complex computed expression; $ifnull
+var p7 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ theSum : { $add:["$pageViews",
+ { $ifnull:["$other.foo",
+ "$other.bar"] } ] }
+ }}
+]});
+
+// dotted path inclusion; _id exclusion
+var p8 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ _id : 0,
+ author : 1,
+ tag : { $unwind : "tags" },
+ "comments.author" : 1
+ }}
+]});
+
+
+// simple matching
+var m1 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $match : { author : "dave" } }
+]});
+
+// combining matching with a projection
+var m2 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ title : 1,
+ author : 1,
+ pageViews : 1,
+ tag : { $unwind : "tags" },
+ comments : 1
+ }},
+ { $match : { tag : "nasty" } }
+]});
+
+
+// group by tag
+var g1 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ tag : { $unwind : "tags" },
+ pageViews : 1
+ }},
+ { $group : {
+ _id: { tag : 1 },
+ docsByTag : { $sum : 1 },
+ viewsByTag : { $sum : "$pageViews" }
+ }}
+]});
+
+// $max, and averaging in a final projection
+var g2 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ tag : { $unwind : "tags" },
+ pageViews : 1
+ }},
+ { $group : {
+ _id: { tag : 1 },
+ docsByTag : { $sum : 1 },
+ viewsByTag : { $sum : "$pageViews" },
+ mostViewsByTag : { $max : "$pageViews" },
+ }},
+ { $project : {
+ _id: false,
+ tag : "_id.tag",
+ mostViewsByTag : 1,
+ docsByTag : 1,
+ viewsByTag : 1,
+ avgByTag : { $divide:["$viewsByTag", "$docsByTag"] }
+ }}
+]});
+
+// $push as an accumulator; can pivot data
+var g3 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ tag : { $unwind : "tags" }
+ }},
+ { $group : {
+ _id : { tag : 1 },
+ authors : { $push : "$author" }
+ }}
+]});
+
+// $avg, and averaging in a final projection
+var g4 = db.runCommand(
+{ aggregate : "article", pipeline : [
+ { $project : {
+ author : 1,
+ tag : { $unwind : "tags" },
+ pageViews : 1
+ }},
+ { $group : {
+ _id: { tag : 1 },
+ docsByTag : { $sum : 1 },
+ viewsByTag : { $sum : "$pageViews" },
+ avgByTag : { $avg : "$pageViews" },
+ }}
+]});
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