Hi @lizou ,
Can you please check again in your .csv file if the value is appended with zeros and stored as a string only, as per the post I believe you are fine to store the number as a string, and I am not facing any issues.
I tried to replicate the same as mentioned below
Created a .csv file with numbers as text with zeros at the start and manually uploaded in UI of the data tab in databricks and read into df , working fine without any issues as shown below,
Please let me know if this answers your query
Happy Learning!!