added distinct, fixed: some issues

Author: nahid

src/Queriable.php

@@ -315,7 +315,8 @@ protected function prepareResult($data)
             }
         } elseif (is_array($data) && count($data) != 0) {
            // $value = json_decode(json_encode($this->takeColumn($data)), true);
-            $output = $this->instanceWithValue($data, ['_select' => $this->_select, '_except' => $this->_except]);
+            //$output = $this->instanceWithValue($data, ['_select' => $this->_select, '_except' => $this->_except]);
+            $output = $this->takeColumn($data);
         } else {
             $output = $data;
         }

src/QueryEngine.php

@@ -409,6 +409,31 @@ public function countGroupBy($column)
         return $this;
     }
 
+
+    /**
+     * getting distinct data from specific column
+     *
+     * @param string $column
+     * @return $this
+     * @throws ConditionNotAllowedException
+     */
+    public function distinct($column)
+    {
+        $this->prepare();
+
+        $data = [];
+        foreach ($this->_map as $map) {
+            $value = $this->getFromNested($map, $column);
+            if ($value && !array_key_exists($value, $data)) {
+                $data[$value] = $map;
+            }
+        }
+
+        $this->_map = array_values($data);
+        return $this;
+    }
+
+
     /**
      * count prepared data
      *