There is no way to “insert” new columns in the middle of the table. If you really want to do that, you would need to
- Backup the information currently in your table.
- Drop the columns that are after the position where you want to new one.
- Add the new column.
- Add the other columns you dropped.
- Insert the data for the columns that were dropped from the backup.
You could also drop the whole table (after backing it up) and re-create it with the new structure, and then re-insert the data.