protected function get_instance_sql() {
        global $DB;
        if ($this->_instancessql === null) {
            $instances = $this->get_enrolment_instances();
            $filter = $this->get_enrolment_filter();
            if ($filter && array_key_exists($filter, $instances)) {
                $sql = " = :ifilter";
                $params = array('ifilter'=>$filter);
            } else {
                $filter = 0;
                if ($instances) {
                    list($sql, $params) = $DB->get_in_or_equal(array_keys($this->get_enrolment_instances()), SQL_PARAMS_NAMED);
                } else {
                    // no enabled instances, oops, we should probably say something
                    $sql = "= :never";
                    $params = array('never'=>-1);
                }
            }
            $this->instancefilter = $filter;
            $this->_instancessql = array($sql, $params, $filter);
        }
        return $this->_instancessql;
    }
protected function get_instance_sql() {
        global $DB;
        if ($this->_instancessql === null) {
            $instances = $this->get_enrolment_instances();
            $filter = $this->get_enrolment_filter();
            if ($filter && array_key_exists($filter, $instances)) {
                $sql = " = :ifilter";
                $params = array('ifilter'=>$filter);
            } else {
                $filter = 0;
                if ($instances) {
                    list($sql, $params) = $DB->get_in_or_equal(array_keys($this->get_enrolment_instances()), SQL_PARAMS_NAMED);
                } else {
                    // no enabled instances, oops, we should probably say something
                    $sql = "= :never";
                    $params = array('never'=>-1);
                }
            }
            $this->instancefilter = $filter;
            $this->_instancessql = array($sql, $params, $filter);
        }
        return $this->_instancessql;
    }
protected function get_instance_sql ( ) { global $ DB ; if ( $ this -> _instancessql === null ) { $ instances = $ this -> get_enrolment_instances ( ) ; $ filter = $ this -> get_enrolment_filter ( ) ; if ( $ filter && array_key_exists ( $ filter , $ instances ) ) { $ sql = " = :ifilter" ; $ params = array ( 'ifilter' => $ filter ) ; } else { $ filter = 0 ; if ( $ instances ) { list ( $ sql , $ params ) = $ DB -> get_in_or_equal ( array_keys ( $ this -> get_enrolment_instances ( ) ) , SQL_PARAMS_NAMED ) ; } else { // no enabled instances, oops, we should probably say something $ sql = "= :never" ; $ params = array ( 'never' => - 1 ) ; } } $ this -> instancefilter = $ filter ; $ this -> _instancessql = array ( $ sql , $ params , $ filter ) ; } return $ this -> _instancessql ; }
Gets an array containing some SQL to user for when selecting, params for
that SQL, and the filter that was used in constructing the sql.

@global moodle_database $DB
@return string
Gets an array containing some SQL to user for when selecting params for that SQL and the filter that was used in constructing the sql .