fix #503 by adding at time zone special syntax

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changes
 
 * 2.4.next in progress
+  * Address [#503](https://github.com/seancorfield/honeysql/issues/503) by adding `:at-time-zone` special syntax.
   * Address [#504](https://github.com/seancorfield/honeysql/issues/504) for BigQuery support, by adding special syntax for ignore/respect nulls, as well as new `:distinct` and `:expr` clauses to allow expressions to be qualified with SQL clauses. The latter will probably be useful for other dialects too.
 
 * 2.4.1066 -- 2023-08-27

doc/special-syntax.md

@@ -68,6 +68,19 @@ In addition, the argument to `:array` is treated as a literal sequence of Clojur
 ;;=> ["SELECT ARRAY[inline, (?, ?, ?)] AS arr" 1 2 3]
 ```
 
+## at time zone
+
+Accepts two arguments: an expression (assumed to be a date/time of some sort)
+and a time zone name or identifier (can be a string, a symbol, or a keyword):
+
+```clojure
+(sql/format-expr [:at-time-zone [:now] :utc])
+;;=> ["NOW() AT TIME ZONE 'UTC'"]
+```
+
+The time zone name or identifier will be inlined (as a string) and therefore
+cannot be an expression.
+
 ## between
 
 Accepts three arguments: an expression, a lower bound, and

src/honey/sql.cljc

@@ -1632,6 +1632,7 @@
     :primary-key #'function-0
     :references  #'function-1
     :unique      #'function-1-opt
+    ;; dynamic dotted name creation:
     :.           (fn [_ [expr col subcol]]
                    (let [[sql & params] (format-expr expr)]
                      (into [(str sql "." (format-entity col)
@@ -1658,6 +1659,13 @@
       (let [[sqls params] (format-expr-list arr)
             type-str (when type (str "::" (sql-kw type) "[]"))]
         (into [(str "ARRAY[" (str/join ", " sqls) "]" type-str)] params)))
+    :at-time-zone
+    (fn [_ [expr tz]]
+      (let [[sql & params] (format-expr expr {:nested true})
+            [tz-sql & _]
+            (binding [*inline* true]
+              (format-expr (if (ident? tz) (name tz) tz)))]
+        (into [(str sql " AT TIME ZONE " tz-sql)] params)))
     :between
     (fn [_ [x a b]]
       (let [[sql-x & params-x] (format-expr x {:nested true})

test/honey/sql_test.cljc

@@ -1261,6 +1261,14 @@ ORDER BY id = ? DESC
   (is (= ["INSERT INTO foo (bar) OUTPUT inserted.* VALUES (?)" 1]
          (sut/format {:insert-into :foo :columns [:bar] :output [:inserted.*] :values [[1]]}))))
 
+(deftest at-time-zone-503
+  (is (= ["SELECT foo AT TIME ZONE 'UTC'"]
+         (sut/format {:select [[[:at-time-zone :foo "UTC"]]]})))
+  (is (= ["SELECT foo AT TIME ZONE 'UTC'"]
+         (sut/format {:select [[[:at-time-zone :foo :UTC]]]})))
+  (is (= ["SELECT FOO(bar) AT TIME ZONE 'UTC'"]
+         (sut/format {:select [[[:at-time-zone [:foo :bar] :UTC]]]}))))
+
 (comment
   ;; partial workaround for #407:
   (sut/format {:select :f.* :from [[:foo [:f :for :system-time]]] :where [:= :f.id 1]})