public function addExpression($name, $expression = null)
    {
        /** @type Field_Expression $f */
        $f = $this->add('Field_Expression', $name);

        return $f->set($expression);
    }
public function addExpression($name, $expression = null)
    {
        /** @type Field_Expression $f */
        $f = $this->add('Field_Expression', $name);

        return $f->set($expression);
    }
public function addExpression ( $ name , $ expression = null ) { /** @type Field_Expression $f */ $ f = $ this -> add ( 'Field_Expression' , $ name ) ; return $ f -> set ( $ expression ) ; }
Adds and returns SQL-calculated expression as a read-only field.

See Field_Expression class.

@param string $name
@param mixed $expression

@return DB_dsql
Adds and returns SQL - calculated expression as a read - only field .