Hi Christel,
As described in
Connecting Data to a Report help topic, Telerik Reporting does depend on a number of "standard" for the .NET framework data source interfaces. To connect to a specific database you should use an appropriate ADO.NET data provider which is responsible for all operations with this database. In the case of MySQL I guess one should use the
MySQL Connector.
As far as the database support is concerned Telerik Reporting is limited to the number of databases that has appropriate ADO.NET data providers (which covers most of the popular databases).
Back to the problem. If I have understood you correctly, your query works fine in the MySQL query browser but you have hard time editing the MySQL data adapter. Unfortunately this is beyond our competence and the only thing I would suggest is to avoid using the data set designer.
As far as we recall we've already advised you in a response to a previous thread to use the data set designer to edit your query. But if you experience any troubles with the data set designer you still have a chance to edit the query (by hand). In the Solution Explorer locate your data set (the typed data sets files has .XSD extension), right click to open the context menu and choose the "Open With ..." option. From the Open With- dialog please select the "XML Editor" option and press the OK button. This will open the typed data set file in the XML editor instead in the data set designer. Locate the SelectCommand/DbCommand element where is the actual query and replace it with the new one (this is usually near the top of the file and the path should be something like this: DataSource/Tables/TableAdapter/MainSource/DbSource/SelectCommand/DbCommand). Saving the XSD file should case the underlying code to be re-generated and from now on the new query should take effect. I know this is not the best way to edit a typed data set but may save you in case you have hard time using the default Visual Studio Data Set designer.
Regards,
Svetoslav
the Telerik team