How many tables do you have, and what are their sizes? I'm asking because if you're considering migrating to PostgreSQL, starting from scratch might be cleaner. This approach will also help you gain a deeper understanding of how data types are handled in PostgreSQL compared to MSSQL.
Can anyone please give me a command to how to migrate those data? I do not have MS' graphic studio GUI but I can access this database using "Navicat Lite"(IP:Port login).