Unanswered: NULL values to '' widthin GROUP BY processing
I have some left outer joins. The data within the fields is always of varchar or integer type. Querying the data will never send back NULL-values, because the default value of strings is set to an empty string. But in my outer joins there appear NULL-values.
The queries have to support a Pervasive DB and my MySQL DB. The Pervasive DB groups NULL values and empty strings to one group, but MySQL doesn't. The result looks like this: