Thank you !! I manage to open the excel file but it only opens one of the files inside the folder. How can I do if I need it to open all of them and join them together in order to create a new file with them.
After I manage to do that, Is there a way that every time there is a new file, it is added to the file created with the other folder?
what does the error say? I assume that it has something to do that the structure of those files are not identical? You could try to use the “Fail if schemas differ” Option in the Advanced settings tabs. As stated in one of my posts above you could use the loop and configure the Excel Reader node to read only one file or get rid of the loop and use the “Files in Folder” option of the Excel Reader node.
Probably what happened there is during the Loop End, some of the data from Excel had different types in the same column (for example, number AND string). This can cause KNIME to generate a column with a “?” column type. You could try the Table Manipulator node to change the type to what you need prior to writing to Excel.
@Melanie_CH maybe you can take a look at this example how to import all the sheets from all Excel files in a folder and bring them into KNIME and export the collected data and write out another Excel File (per sheet name). You can obviously change the settings and methods of collection: