+ [misc] add columnExistInOriginTable.

lib/sqlparser/sqlparser.class.php

@@ -71,6 +71,22 @@ class sqlparser
         $this->isSelect = $this->statement instanceof PhpMyAdmin\SqlParser\Statements\SelectStatement === true;
     }
 
+    /**
+     * Judge column exist in origin table or not.
+     *
+     * @param  string    $table
+     * @param  string    $column
+     * @access public
+     * @return bool
+     */
+    public function columnExistInOriginTable($table, $column)
+    {
+        $originTable = $this->getOriginTableColumns($table);
+        if(!$originTable) return false;
+
+        return isset($originTable[$column]);
+    }
+
     /**
      * Get origin table columns.
      *