How can I join two tables on the name, while they have underscore?
For example:

```
SELECT       *
FROM        table1
INNER JOIN  table2
ON          table1.stringColumn = table2.stringColumn
WHERE       table1.stringColumn!= '';

```

This doesn't work if table1.stringColumn= test12\_42 and table2.stringColumn= test12\_42.

How can I join them, altought the names have umlaute and underscores?