final public function sqlIsNull(string $field, bool $positive = true): string
    {
        if (! $positive) {
            trigger_error(
                __METHOD__ . ' with argument $positive = false is deprecated, use DBAL::sqlIsNotNull',
                E_USER_NOTICE
            );
            return $this->sqlIsNotNull($field);
        }
        return $field . ' IS NULL';
    }
final public function sqlIsNull(string $field, bool $positive = true): string
    {
        if (! $positive) {
            trigger_error(
                __METHOD__ . ' with argument $positive = false is deprecated, use DBAL::sqlIsNotNull',
                E_USER_NOTICE
            );
            return $this->sqlIsNotNull($field);
        }
        return $field . ' IS NULL';
    }
final public function sqlIsNull ( string $ field , bool $ positive = true ) : string { if ( ! $ positive ) { trigger_error ( __METHOD__ . ' with argument $positive = false is deprecated, use DBAL::sqlIsNotNull' , E_USER_NOTICE ) ; return $ this -> sqlIsNotNull ( $ field ) ; } return $ field . ' IS NULL' ; }
Return a comparison condition against null

@param string $field
@param bool $positive Set to FALSE to perform a IS NOT NULL comparison
@return string
Return a comparison condition against null