Skip to content

Instantly share code, notes, and snippets.

@cwestin
Created November 28, 2011 19:12
Show Gist options
  • Save cwestin/1401585 to your computer and use it in GitHub Desktop.
Save cwestin/1401585 to your computer and use it in GitHub Desktop.
Mongo shell script and sample documents used for my aggregation talks 12/2011
// make sure we're using the right db; this is the same as "use aggdb;" in shell
db = db.getSiblingDB("aggdb");
// simple projection
var p1 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $project : {
tags : 1,
pageViews : 1
}}
]});
// unwinding an array
var u1 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $unwind : "$tags" }
]});
// combining pipeline operations
var p2 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $project : {
author : 1,
tags : 1,
pageViews : 1
}},
{ $unwind : "$tags" }
]});
// 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,
tags : 1
}},
{ $unwind : "$tags" },
{ $project : {
author : 1,
subDocument : { foo : "$pageViews", bar : "$tags" }
}}
]});
// nested 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,
tags : 1,
"comments.author" : 1
}}
]});
// simple sort
var p10 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $sort : { title : 1 }
}
]});
// date tests
var p19 = db.runCommand(
{aggregate : "article", pipeline : [
{ $project : {
authors : 1,
seconds: {$second: "$posted"},
minutes: {$minute: "$posted"},
hour: {$hour: "$posted"},
dayOfYear: {$dayOfYear: "$posted"},
dayOfMonth: {$dayOfMonth: "$posted"},
dayOfWeek: {$dayOfWeek: "$posted"},
month: {$month: "$posted"},
week: {$week: "$posted"},
year: {$year: "$posted"}
}}
]});
// ternary conditional operator
var p21 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $project : {
_id : 0,
author : 1,
pageViews : { $cond : [ {$eq:["$author", "dave"]},
{$add:["$pageViews", 1000]}, "$pageViews" ]
}
}}
]});
// 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,
tags : 1,
comments : 1
}},
{ $unwind : "$tags" },
{ $match : { tags : "nasty" } }
]});
// grouping
var g1 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $project : {
author : 1,
tags : 1,
pageViews : 1
}},
{ $unwind : "$tags" },
{ $group : {
_id : "$tags",
docsByTag : { $sum : 1 },
viewsByTag : { $sum : "$pageViews" },
mostViewsByTag : { $max : "$pageViews" },
avgByTag : { $avg : "$pageViews" }
}}
]});
// $addToSet as an accumulator; can pivot data
var g5 = db.runCommand(
{ aggregate : "article", pipeline : [
{ $project : {
author : 1,
tags : 1,
}},
{ $unwind : "$tags" },
{ $group : {
_id : { tags : 1 },
authors : { $addToSet : "$author" }
}}
]});
/* sample articles for aggregation demonstrations */
// make sure we're using the right db; this is the same as "use mydb;" in shell
db = db.getSiblingDB("aggdb");
db.article.drop();
db.article.save( {
title : "this is my title" ,
author : "bob" ,
posted : new Date(1079895594000) ,
pageViews : 5 ,
tags : [ "fun" , "good" , "fun" ] ,
comments : [
{ author :"joe" , text : "this is cool" } ,
{ author :"sam" , text : "this is bad" }
],
other : { foo : 5 }
});
db.article.save( {
title : "this is your title" ,
author : "dave" ,
posted : new Date(4121381470000) ,
pageViews : 7 ,
tags : [ "fun" , "nasty" ] ,
comments : [
{ author :"barbara" , text : "this is interesting" } ,
{ author :"jenny" , text : "i like to play pinball", votes: 10 }
],
other : { bar : 14 }
});
db.article.save( {
title : "this is some other title" ,
author : "jane" ,
posted : new Date(978239834000) ,
pageViews : 6 ,
tags : [ "nasty" , "filthy" ] ,
comments : [
{ author :"will" , text : "i don't like the color" } ,
{ author :"jenny" , text : "can i get that in green?" }
],
other : { bar : 14 }
});
@asya999
Copy link

asya999 commented Aug 29, 2012

In 2.2 you can do db.result.save(r.result) since 2.2 will save an array into multiple documents (one per array entry).

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment