Question About Data Import In MS-SQL Server

Dear All,

I am performing a data import on the SQL server. Due to fact
that I use the excel file as a source. Some of cells in excel are
actually empty, they become NULL fields after importing into the SQL
server. Actually I want these fields are empty string instead of NULL.
Does SQL server has any approach to make these fields to be empty
string instead of NULL when importing?? Or is there any store
procedure exist for converting the fields to empty string?

Thanks for your kind attention.

Benny