library/database/class.sqldriver.php
public function Distinct($Bool = TRUE) {
      $this->_Distinct = (is_bool($Bool)) ? $Bool : TRUE;
      return $this;
   }
public function Distinct($Bool = TRUE) {
      $this->_Distinct = (is_bool($Bool)) ? $Bool : TRUE;
      return $this;
   }
public function Distinct ( $ Bool = TRUE ) { $ this -> _Distinct = ( is_bool ( $ Bool ) ) ? $ Bool : TRUE ; return $ this ; }
Specifies that the query should be run as a distinct so that duplicate
columns are grouped together. Returns this object for chaining purposes.

@param boolean $Bool A boolean value indicating if the query should be distinct or not.
Specifies that the query should be run as a distinct so that duplicate columns are grouped together . Returns this object for chaining purposes .