fix #527 by adding tests for composite and documenting its use in more detail

both from clause and composite special syntax have examples now

Signed-off-by: Sean Corfield <sean@corfield.org>

doc/clause-reference.md

@@ -815,6 +815,17 @@ user=> (sql/format {:select [:u.username :s.name]
 ["SELECT u.username, s.name FROM user AS u, status AS s WHERE (u.statusid = s.id) AND (u.id = ?)" 9]
 ```
 
+`:from` can also accept a `:values` clause:
+
+```clojure
+user=> (sql/format {:update :table :set {:a :v.a}
+                    :from [[{:values [[1 2 3]
+                                      [4 5 6]]}
+                            [:v [:composite :a :b :c]]]]
+                    :where [:and [:= :x :v.b] [:> :y :v.c]]})
+["UPDATE table SET a = v.a FROM (VALUES (?, ?, ?), (?, ?, ?)) AS v (a, b, c) WHERE (x = v.b) AND (y > v.c)" 1 2 3 4 5 6]
+```
+
 As of 2.4.1066, HoneySQL supports a temporal clause that starts with `:for`,
 followed by the time reference
 (e.g., `:system-time` or `:business-time`), followed by a temporal qualifier,

doc/special-syntax.md

@@ -174,6 +174,23 @@ expression (comma-separated, wrapped in parentheses):
 ;;=> ["(a, b, ?, x + ?)" "red" 1]
 ```
 
+This can be useful in a number of situations where you want a composite
+value, as above, or a composite based on or declaring columns names:
+
+```clojure
+(sql/format {:select [[[:composite :a :b] :c]] :from :table})
+;;=> ["SELECT (a, b) AS c FROM table"]
+```
+
+```clojure
+(sql/format {:update :table :set {:a :v.a}
+             :from [[{:values [[1 2 3]
+                               [4 5 6]]}
+                     [:v [:composite :a :b :c]]]]
+             :where [:and [:= :x :v.b] [:> :y :v.c]]})
+;;=> ["UPDATE table FROM (VALUES (?, ?, ?), (?, ?, ?)) AS v (a, b, c) SET a = v.a WHERE (x = v.b) AND (y > v.c)" 1 2 3 4 5 6]
+```
+
 ## distinct
 
 Accepts a single expression and prefixes it with `DISTINCT `:

src/honey/sql.cljc

@@ -341,7 +341,7 @@
   (when k
     (let [n (str/replace (name k) "?" "??")]
       (if (= \' (first n))
-        (let [ident   (subs n 1 (count n))
+        (let [ident   (subs n 1)
               ident-l (str/lower-case ident)]
           (binding [*quoted* (when-not (contains? #{"array"} ident-l) *quoted*)]
             (format-entity (keyword ident))))

test/honey/sql_test.cljc

@@ -1341,10 +1341,26 @@ ORDER BY id = ? DESC
             (= ["SELECT * FROM table WITH (DEF, ABC)"]
                (sut/format {:select [:*] :from [^{:abc true :def true} [:table]]}))))))
 
+(deftest issue-527-composite
+  (is (= ["SELECT (a, b) AS c FROM table"]
+         (sut/format {:select [[[:composite :a :b] :c]] :from [:table]})))
+  (is (= ["SELECT a FROM table WHERE (b, c) = (?, ?)" 1 2]
+         (sut/format {:select :a :from :table :where [:= [:composite :b :c] [:composite 1 2]]})))
+  (is (= ["SELECT a, b, c FROM (VALUES (?, ?, ?), (?, ?, ?)) AS t (a, b, c)" 1 2 3 4 5 6]
+         (sut/format {:select [:a :b :c]
+                      :from [[{:values [[1 2 3] [4 5 6]]}
+                              [:t [:composite :a :b :c]]]]}))))
+
 (comment
   ;; partial (incorrect!) workaround for #407:
   (sut/format {:select :f.* :from [[:foo [:f :for :system-time]]] :where [:= :f.id 1]})
   ;; correct version:
   (sut/format {:select :f.* :from [[:foo :f :for :system-time]] :where [:= :f.id 1]})
   (sut/format {:where [:= :x [:inline :DATE "2019-01-01"]]})
+  ;; https://github.com/seancorfield/honeysql/issues/526
+  (->
+   {:create-table-as [:a-b.b-c.c-d]
+    :select          [:*]
+    :from            [:a-b.b-c.c-d]}
+   (sut/format {:dialect :nrql}))
   )