If your data is messy (=multiple data types appearing within 1 column) and you want to make sure that everything will be successfully uploaded to BigQuery, you should use “All …
If you want to retain control over data types for each column in your table, you can use Manual option in the Data Types dropdown. The down side is that …
If you are lazy person like us, you will likely want to use Autodetect option for detecting the data types: This is a very helpful option when your table has …