It is not currently possible to set null values in the SQL Database Connector. Essentially, because of the backend logic behind this feature, and the way Bubble casts certain objects, blank text is actually cast as an empty string, instead of a null value in the database. This casting does not allow us to render any blank Bubble Text to a null value.

While we cannot offer a true workaround for this at this time, there is the ability to force a null replacement with nullif in the SQL Database Connector. Thus, by using NULLIF(FIELD,""), Bubble will treat this as an empty string if null is passed in.