From 9cf71871f3768bfd7f7b9912cc13a3e5c275a626 Mon Sep 17 00:00:00 2001
From: Niels van Klaveren <github@kometa.demon.nl>
Date: Tue, 19 Aug 2014 11:11:09 +0200
Subject: [PATCH] Added OVER (PARTITION BY) clause

Supports windowed aggregate functions as fields
{:aggregate :%fn.field :over {:partition-by [:field]}}
---
 src/honeysql/format.clj  | 15 ++++++++++++++-
 src/honeysql/helpers.clj | 25 ++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/src/honeysql/format.clj b/src/honeysql/format.clj
index b42b020..db587a3 100644
--- a/src/honeysql/format.clj
+++ b/src/honeysql/format.clj
@@ -183,6 +183,9 @@
    :right-join 140
    :full-join 150
    :where 160
+   :aggregate 162
+   :over 165
+   :partition 167
    :group-by 170
    :having 180
    :order-by 190
@@ -455,7 +458,17 @@
 
 (defmethod format-clause :delete-from [[_ table] _]
   (str "DELETE FROM " (to-sql table)))
-  
+
+(defmethod format-clause :over [[_ part-clause] _]
+  (str "OVER " (to-sql part-clause)))
+
+(defmethod format-clause :aggregate [[_ aggregate-fn] _]
+  (str (to-sql aggregate-fn)))
+
+(defmethod format-clause :partition-by [[_ fields] _]
+  (str "PARTITION BY "
+       (comma-join (map to-sql fields))))
+
 (defn cte->sql
   [[cte-name query]]
   (str (to-sql cte-name) " AS " (to-sql query)))
diff --git a/src/honeysql/helpers.clj b/src/honeysql/helpers.clj
index e94eae6..8c12d7a 100644
--- a/src/honeysql/helpers.clj
+++ b/src/honeysql/helpers.clj
@@ -219,7 +219,30 @@
 (defn delete-from
   ([table] (delete-from nil table))
   ([m table] (build-clause :delete-from m table)))
-  
+
+(defmethod build-clause :over [_ m table]
+  (assoc m :over table))
+
+(defn over
+  ([part-clause] (over nil part-clause))
+  ([m part-clause] (build-clause :over m part-clause)))
+
+(defhelper merge-over [m fields]
+  (update-in m [:over] (partial apply merge) (collify fields)))
+
+(defhelper aggregate [m aggregate-fn]
+  (assoc m :aggregate aggregate-fn))
+
+(defn aggregate
+  ([table] (aggregate nil table))
+  ([m table] (build-clause :aggregate m table)))
+
+(defhelper spartition-by [m fields]
+  (assoc m :partition-by (collify fields)))
+
+(defhelper merge-partition-by [m fields]
+  (update-in m [:partition-by] concat (collify fields)))
+
 (defmethod build-clause :with [_ m ctes]
   (assoc m :with ctes))