IssueWhen you try to filter on a calculated field that contains "NULL", the following error occurs:
An error occured while communicating with data source...
The connection to the data source might have been lost.
[MySQL][ODBC 5.3(w) Driver][mysqld-5.1.33-community]Illegal mix of collations (utf8_bin,NONE) AND (utf8_general,COERCIBLE) for operation
prepare.xml class DataSourceException