MongoDB: Aggregation
db.whisky.aggregate( [
{ $match: { region_slug: /^scotland-/ } },
{ $group : {
_id: '$region',
whiskies: { '$push' : '$name' }
} }
] );
db.whisky.aggregate( [
{ *$match*: { region_slug: */^scotland-/* } },
{ $group : {
_id: '$region',
whiskies: { '$push' : '$name' }
} }
] );
*$match* with regular expression
db.whisky.aggregate( [
{ $match: { region_slug: /^scotland-/ } },
{ *$group* : {
_id: *'$region'*,
whiskies: { '$push' : '$name' }
} }
] );
$match with regular expression
*$group* by the value of *$region*
db.whisky.aggregate( [
{ $match: { region_slug: /^scotland-/ } },
{ $group : {
_id: *'$region'*,
whiskies: { *'$push' : '$name'* }
} }
] );
$match with regular expression
$group by the value of $region
For each matched document, add *$name* to correct bucket
{ "_id" : "Scotland, Lowlands", "whiskies" : [ "Cambus 26" ] }
{ "_id" : "Scotland, Speyside", "whiskies" : [ "Glenfarclas 15", "Glen Spey-Glenlivet 19", "Glenrothes-Glenlivet 24", "Glen Grant-Glenlivet 20", "Glen Mohr 23", "Glenfiddich 12", "Glen Moray New Whisky Test 12", "yamazaki 15", "Yamazaki 13", "Cuba Cask End 18" ] }
{ "_id" : "Scotland, Islay", "whiskies" : [ "Bunnahabhain 18", "Auriverdes", "Bunnahabhain 12", "Bowmore 12 Wine Cask", "Laphroaig 18" ] }
{ "_id" : "Scotland, Islands", "whiskies" : [ "Arran 12", "Talisker 10" ] }
{ "_id" : "Scotland, Campbeltown", "whiskies" : [ "Hazelburn 10" ] }
{ "_id" : "Scotland, Highlands", "whiskies" : [ "Glengoyne 14", "Ord 10 +3", "Glen 23", "Glen 24", "Glen 25", "New Dram With Unknown Bottler", "Yamazaki 18", "Yamazaki 16", "Yamazaki 14", "Glengoyne-14" ] }