Couchbase対MongoDB™：パフォーマンスとスケーラビリティの比較

/* Mongoの例に相当 */
SELECT SUM(value * volume) AS val, symbol
FROM   db.stocks
WHERE  symbol IN ( "AAPL", "GOOG" ) AND value > 0
GROUP  BY symbol
ORDER  BY val DESC, symbol ASC

// SQL++の例と同等
db.stocks.aggregate([
     { "$match": {
          "$and": [
               {"symbol": {
	 	 	 	 "$in": [
                    "AAPL",
                    "GOOG"]}},
               { "value": {
	 	 	 "$gt": 0 }}]}},
     { "$group": {
          "_id": {
               "symbol": "$symbol" },
	 	 "sum(value * volume)": {
               "$sum": {
                    "$multiply": [
                         "$value",
	 	 	 	 	 "$volume"]}}}},
     { "$project": {
	 	 "_id": 0,
          "sum(value * volume)": "$sum(value * volume)",
          "symbol": "$_id.symbol"}}
	 { "$sort": {
          "sum(value * volume)": -1,
          "symbol": 1 }}]})