For some reason there is a difference in the first loaded table's fields, and the fields in the subsequent tables. I suggest that you post your script, and if possible two of the excel files (just the first 5-10 lines) for further diagnosis. As the previous post said, they should have been auto-concatenated.
I found that the my first file is slightly different from the rest of the files.
All the fields in the LOAD session are available for all the excel files but the first file is an old version which means the order of the fields is different and some of the new fields are not included.
Do you think that could be the reason?
It it is, how can I make them into one table?
Thank you very much for your time.