Issue #24 Add group_by_expr function

README.markdown

@@ -35,6 +35,7 @@ Changelog
 * Patch to allow empty Paris models to be saved ([[j4mie/paris](http://github.com/j4mie/paris)]) issue #58
 * Add `select_many` and `select_many_expr` - closing issues #49 and #69
 * Add support for `MIN`, `AVG`, `MAX` and `SUM` - closes issue #16
+* Add `group_by_expr` - closes issue #24
 
 #### 1.1.1 - release 2011-01-30
 
@@ -230,7 +231,11 @@ If you want to order by something other than a column name, then use the `order_
 
 To add a `GROUP BY` clause to your query, call the `group_by` method, passing in the column name. You can call this method multiple times to add further columns.
 
-    $poeple = ORM::for_table('person')->where('gender', 'female')->group_by('name')->find_many();
+    $people = ORM::for_table('person')->where('gender', 'female')->group_by('name')->find_many();
+
+It is also possible to `GROUP BY` a database expression:
+
+    $people = ORM::for_table('person')->where('gender', 'female')->group_by_expr("FROM_UNIXTIME(`time`, '%Y-%m')")->find_many();
 
 #### Result columns ####
 

idiorm.php

@@ -913,6 +913,14 @@ public function group_by($column_name) {
             return $this;
         }
 
+        /**
+         * Add an unquoted expression to the list of columns to GROUP BY 
+         */
+        public function group_by_expr($expr) {
+            $this->_group_by[] = $expr;
+            return $this;
+        }
+
         /**
          * Build a SELECT statement based on the clauses that have
          * been passed to this instance by chaining method calls.

test/test_queries.php

@@ -112,6 +112,10 @@
     $expected = "SELECT * FROM `widget` GROUP BY `name`, `age`";
     Tester::check_equal("Multiple GROUP BY", $expected);
 
+    ORM::for_table('widget')->group_by_expr("FROM_UNIXTIME(`time`, '%Y-%m')")->find_many();
+    $expected = "SELECT * FROM `widget` GROUP BY FROM_UNIXTIME(`time`, '%Y-%m')";
+    Tester::check_equal("GROUP BY expression", $expected);
+
     ORM::for_table('widget')->where('name', 'Fred')->limit(5)->offset(5)->order_by_asc('name')->find_many();
     $expected = "SELECT * FROM `widget` WHERE `name` = 'Fred' ORDER BY `name` ASC LIMIT 5 OFFSET 5";
     Tester::check_equal("Complex query", $expected);