Per the title, if you try to run an importer and you enter a numeric import log table name (ex: 20171211) during configuration, an exception is thrown.
XF\Db\InvalidQueryException: MySQL statement prepare error [1064]: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '20171215 (`content_type`, `old_id`, `new_id`) VALUES (?, ?, ?) ON DUPLICATE KEY ' at line 1 in src/XF/Db/AbstractStatement.php at line 212
XF\Db\AbstractStatement->getException() insrc/XF/Db/Mysqli/Statement.php at line 174
XF\Db\Mysqli\Statement->getException() insrc/XF/Db/Mysqli/Statement.php at line 35
XF\Db\Mysqli\Statement->prepare() in src/XF/Db/Mysqli/Statement.phpat line 46
XF\Db\Mysqli\Statement->execute() in src/XF/Db/AbstractAdapter.phpat line 69
XF\Db\AbstractAdapter->query() in src/XF/Db/AbstractAdapter.php at line 145
XF\Db\AbstractAdapter->insert() in src/XF/Import/Log.php at line 117
XF\Import\Log->log() in src/XF/Import/DataManager.php at line 116
XF\Import\DataManager->log() insrc/XF/Import/Data/AbstractData.php at line 105
XF\Import\Data\AbstractData->save() insrc/addons/SV/ContentRatings/Import/Importer/PostRatings.php at line215
SV\ContentRatings\Import\Importer\PostRatings->stepRatingTypeCategories() in src/XF/Import/Runner.php at line 161
XF\Import\Runner->runStep() in src/XF/Import/Runner.php at line 75
XF\Import\Runner->run() in src/XF/Admin/Controller/Import.php at line231
XF\Admin\Controller\Import->actionRun() insrc/XF/Mvc/Dispatcher.php at line 249
XF\Mvc\Dispatcher->dispatchClass() in src/XF/Mvc/Dispatcher.php at line88
XF\Mvc\Dispatcher->dispatchLoop() in src/XF/Mvc/Dispatcher.php at line41
XF\Mvc\Dispatcher->run() in src/XF/App.php at line 1879