Create an alternative uniqueness checking

[pkiraly]

> select recordId from issue WHERE filename LIKE 'DDB-DC/Q1_small_DC_BAW/dcIdentifier_identische_Werte%';
+----------+
| recordId |
+----------+
| HB222    |
| HB222    |
+----------+

> select recordId, count(recordId) AS count from issue GROUP BY recordId HAVING count > 1;
+------------------------------------------------+-------+
| recordId                                       | count |
+------------------------------------------------+-------+
| DE-188/ZWAR/za046345                           |     2 |
| DE-2380/40660                                  |     2 |
| DE-MUS-029318/5475                             |     2 |
| HB222                                          |     2 |
| HBdia02176222                                  |     2 |
| oai:baw:85d5d180-9018-4e3d-95b8-11111221111ccc |     2 |
| oai:baw:cd6ae097-b7ca-48fe-bb5c-11111111111    |     2 |
| record_naniweb_463                             |     3 |
| record_naniweb_4635ttt75757                    |     3 |
| umbruch_8 --- umbruch_313604671069             |     2 |
| umbruch_8 --- umbruch_3136hh69                 |     2 |
| UNKNOWN-ID-1                                   |     2 |
| UNKNOWN-ID-2                                   |     2 |
| UNKNOWN-ID-3                                   |     2 |
+------------------------------------------------+-------+
14 rows in set (0,00 sec)