Merge 36d13d32dc into d5a0784e16

src/honeysql/format.clj

@@ -17,6 +17,15 @@
 (defn paren-wrap [x]
   (str "(" x ")"))
 
+;; Checks if the first elemnet of the list is a `DISTINCT ON` statement, if yes
+;; then return a string with an appended space at the end of the first and then
+;; comma joining the rest else simply return a comma joined string
+(defn construct-select [s]
+  (let [[fst & rst] s]
+    (if (re-find #"DISTINCT ON" fst)
+      (str fst " " (comma-join rst))
+      (comma-join s))))
+
 (def ^:dynamic *clause*
   "During formatting, *clause* is bound to :select, :from, :where, etc."
   nil)
@@ -403,7 +412,7 @@
          (str (space-join (map (comp string/upper-case name)
                                (:modifiers sql-map)))
               " "))
-       (comma-join (map to-sql fields))))
+       (construct-select (map to-sql fields))))
 
 (defmethod format-clause :from [[_ tables] _]
   (str "FROM " (comma-join (map to-sql tables))))

test/honeysql/core_test.clj

@@ -174,3 +174,12 @@
                (from :foo)
                (join :x [:= :foo.id :x.id] :y nil)
                sql/format)))))
+
+(deftest distinct-on
+  (testing "Distinct on query generation"
+    (is (= ["SELECT DISTINCT ON (name) name, created_by"]
+           (-> (select (sql/call :distinct-on :name) :name :created_by)
+               sql/format)))
+    (is (= ["SELECT DISTINCT ON (name, created_by) name, created_by"]
+           (-> (select (sql/call :distinct-on :name :created_by) :name :created_by)
+               sql/format)))))