If you are reading SalesForce data into SQL Server through a linked server you might encounter null data errors that look like this:
An unexpected NULL value was returned for column … from OLE DB provider … for linked server … This column cannot be null.
You can be remedy this problem by testing the column that is throwing the null error with the nullif function:
nullif( [ErrorColumn], ””) as ResolvedErrorColumn
(Note: those are 4 single quotes after [ErrorColumn])
A where clause to filter out the nulls of the said data set did not work in my case.