I have a CSV file and each line looks similar to this:
EASTTEXAS,NULL,BELLVILLE AREA,NULL,BELLVILLE AREA,RGP,NULL,NULL,0,NULL,NULL,NULL,1,1,PM,PM Settings,NU
According to:
http://msdn.microsoft.com/en-us/library/ms187887.aspx
null values can be inserted by having an empty field within your file.
Example file was:
1,,DataField3
2,,DataField3
Example method of importing file keeping nulls is:
USE AdventureWorks;
GO
BULK INSERT MyTestDefaultCol2
FROM 'C:\MyTestEmptyField2-c.Dat'
WITH (
DATAFILETYPE = 'char',
FIELDTERMINATOR = ',',
KEEPNULLS
);
GO
Granted, this means you'll have to change your "NULL"s to "", and any empty strings you did want as empty string would be interpreted as nulls, but it might be enough to get you started? I would imagine to keep your empty string columns they would need to be changed from
field1,,field2
to
field1,"",field2
as example