add GROUP BY support

ssql.scm

@@ -48,7 +48,7 @@
                   (,number? . number->sql)
                   (,vector? . vector->sql)))
 
-               ((clauses-order) '(columns from table into set values where order having union))
+               ((clauses-order) '(columns from table into set values where group having order union))
 
                ((escape-string string)
                 (string-translate* string '(("'" . "''"))))
@@ -208,6 +208,7 @@
   (from prefix "FROM" ", ")
   (values prefix "VALUES" ", ")
   (where prefix)
+  (group prefix "GROUP BY" ", ")
   (order prefix "ORDER BY" ", ")
   (having prefix)
   (union infix)

tests/ansi-test.scm

@@ -25,7 +25,14 @@
 
   (test "order"
     "SELECT lastname, firstname FROM people ORDER BY lastname DESC, firstname"
-    (ssql->sql #f '(select (columns lastname firstname) (from people) (order (desc lastname) firstname)))))
+    (ssql->sql #f '(select (columns lastname firstname) (from people) (order (desc lastname) firstname))))
+
+  (test "group"
+    "SELECT actors.name, COUNT(roles.id) FROM roles, actors WHERE (roles.actor_id = actors.id) GROUP BY actors.name"
+    (ssql->sql #f '(select (columns (col actors name) (count (col roles id)))
+                     (from roles actors)
+                     (where (= (col roles actor_id) (col actors id)))
+                     (group (col actors name))))))
 
 (test-group "updates"
   (test "simple case"