Comma separate the column names provided to RETURNING (#48)

* Separate the column names provided to the returning clause by comma
* Test for varying number of returning columns

Author: scimetfoo

src/honeysql_postgres/format.cljc

@@ -130,7 +130,10 @@
   (sqlf/space-join (format-upsert-clause upsert)))
 
 (defmethod format-clause :returning [[_ fields] _]
-  (str "RETURNING " (sqlf/comma-join (map sqlf/to-sql fields))))
+  (->> (flatten fields)
+       (map sqlf/to-sql)
+       (sqlf/comma-join)
+       (str "RETURNING ")))
 
 (defmethod format-clause :create-view [[_ viewname] _]
   (str "CREATE VIEW " (-> viewname

test/honeysql_postgres/postgres_test.cljc

@@ -11,7 +11,8 @@
                                                from order-by update sset query-values
                                                modifiers]]
             [honeysql.core :as sql]
-            [clojure.test :as test :refer [deftest is testing]]))
+            [clojure.test :as test :refer [deftest is testing]]
+            [clojure.string :as str]))
 
 (deftest upsert-test
   (testing "upsert sql generation for postgresql"
@@ -69,14 +70,15 @@
   (testing "returning clause in sql generation for postgresql"
     (is (= ["DELETE FROM distributors WHERE did > 10 RETURNING *"]
            (sql/format {:delete-from :distributors
-                        :where [:> :did :10]
-                        :returning [:*]})))
-    (is (= ["UPDATE distributors SET dname = ? WHERE did = 2 RETURNING did dname" "Foo Bar Designs"]
-           (-> (update :distributors)
-               (sset {:dname "Foo Bar Designs"})
-               (where [:= :did :2])
-               (returning [:did :dname])
-               sql/format)))))
+                        :where       [:> :did :10]
+                        :returning   [:*]})))
+    (doseq [returning-columns (reductions conj [] [:did :dname :nos])]
+      (is (= [(str "UPDATE distributors SET dname = ? WHERE did = 2 RETURNING " (str/join ", " (map name returning-columns))) "Foo Bar Designs"]
+             (-> (update :distributors)
+                 (sset {:dname "Foo Bar Designs"})
+                 (where [:= :did :2])
+                 (returning returning-columns)
+                 sql/format))))))
 
 (deftest create-view-test
   (testing "creating a view from a table"