cascalog-average.clj

(def average
   (<- [!val :> !avg])
      (c/count !count)
      (c/sum !val :> !sum)
      (div !sum !count :> !avg))

cascalog-people-older-than.clj

(defn people-older-than [threshold]
   (<- [?person]
      (age ?person ?age)
      (> ?age threshold)))

cascalog-popular-people.clj

(defn popular-people []
   (<- [?person]
      (follows ?person _)
      (c/count ?count)
      (> ?count 100)))

cascalog-subquery.clj

(defn old-male-people [male-people]
   (<- [?person]
      (male-people ?person)
      (age ?person ?age)
      (> ?age 90)))

cascalog-use-average.clj

(<- [?avg-age]
   (age _ ?age)
   (average ?age :> ?avg-age))

sql-vs-cascalog.clj

;; Find everyone who is 25 years old
"SELECT person FROM Age WHERE age = 25"
(<- [?person] (Age ?person 25))


;; Find all the male people that Emily follows
"SELECT F.target AS person FROM Follows F, Gender G WHERE F.source = "Emily" AND G.gender = "m" AND F.target = G.person"
(<- [?person] (Follows "Emily" ?person) (Gender ?person "m"))


;; Find how many people each person follows
"SELECT source AS person, COUNT(*) AS followscount FROM Follows GROUP BY source"
(<- [?person ?count] (Follows ?person _) (c/count ?count))