How to deselect values in multivalue lookup field using a query

Question

I want to delete all the data of a single field. This field is a ''multipled value lookup field''; I tried this query in the SQL design tab:

UPDATE _myDatabase SET [_myDatabase].mycolumn= Null;

but it's not working (although it works for a any non-lookup fields). Any idea how to solve this?

Answer 1

Because you are using a multi value field, you must treat the field as a separate table, which it actually is under the hood.

So you use a DELETE statement:

DELETE _myDatabase.mycolumn.Value FROM _myDatabase